diff --git a/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache b/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
index 74d2bddc1e8..d0e75fd178c 100644
--- a/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
+++ b/modules/swagger-codegen/src/main/resources/csharp/modelGeneric.mustache
@@ -133,7 +133,7 @@ this.{{name}} = {{name}};
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public {{#parent}}{{^isArrayModel}}override {{/isArrayModel}}{{/parent}}{{^parent}}{{#discriminator}}virtual {{/discriminator}}{{/parent}}string ToJson()
+        public {{#parent}}{{^isArrayModel}}override {{/isArrayModel}}{{/parent}}{{^parent}}virtual {{/parent}}string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithInvalidRequiredEnumUsageOnRef.cs b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithInvalidRequiredEnumUsageOnRef.cs
index 2a9a895ecb2..cbff1a670c7 100644
--- a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithInvalidRequiredEnumUsageOnRef.cs
+++ b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithInvalidRequiredEnumUsageOnRef.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalEnum.cs b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalEnum.cs
index 870174af6ec..a514a1b329f 100644
--- a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalEnum.cs
+++ b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalEnum.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalInlineEnum.cs b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalInlineEnum.cs
index 1acd88ef379..66ce618e981 100644
--- a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalInlineEnum.cs
+++ b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithOptionalInlineEnum.cs
@@ -130,7 +130,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithRequiredInlineEnum.cs b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithRequiredInlineEnum.cs
index ac6c2009b41..dcb3707584a 100644
--- a/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithRequiredInlineEnum.cs
+++ b/modules/swagger-codegen/src/test/resources/integrationtests/csharp/general/enum-support-expected/src/IO.Swagger/Model/MyClassWithRequiredInlineEnum.cs
@@ -143,7 +143,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/.swagger-codegen/VERSION b/samples/client/petstore-security-test/csharp/SwaggerClient/.swagger-codegen/VERSION
index f9f7450d135..50794f17f1a 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/.swagger-codegen/VERSION
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/.swagger-codegen/VERSION
@@ -1 +1 @@
-2.3.0-SNAPSHOT
\ No newline at end of file
+2.3.1-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/README.md b/samples/client/petstore-security-test/csharp/SwaggerClient/README.md
index 15f71dc40fb..d8ed7f1c12d 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/README.md
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/README.md
@@ -17,11 +17,13 @@ This C# SDK is automatically generated by the [Swagger Codegen](https://github.c
 ## Dependencies
 - [RestSharp](https://www.nuget.org/packages/RestSharp) - 105.1.0 or later
 - [Json.NET](https://www.nuget.org/packages/Newtonsoft.Json/) - 7.0.0 or later
+- [JsonSubTypes](https://www.nuget.org/packages/JsonSubTypes/) - 1.2.0 or later
 
 The DLLs included in the package may not be the latest version. We recommend using [NuGet] (https://docs.nuget.org/consume/installing-nuget) to obtain the latest version of the packages:
 ```
 Install-Package RestSharp
 Install-Package Newtonsoft.Json
+Install-Package JsonSubTypes
 ```
 
 NOTE: RestSharp versions greater than 105.1.0 have a bug which causes file uploads to fail. See [RestSharp#742](https://github.com/restsharp/RestSharp/issues/742)
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/build.bat b/samples/client/petstore-security-test/csharp/SwaggerClient/build.bat
index c9f4b1adf4f..d37b6115ab8 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/build.bat
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/build.bat
@@ -11,6 +11,7 @@ if not exist ".\nuget.exe" powershell -Command "(new-object System.Net.WebClient
 if not exist ".\bin" mkdir bin
 
 copy packages\Newtonsoft.Json.10.0.3\lib\net45\Newtonsoft.Json.dll bin\Newtonsoft.Json.dll
+copy packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll bin\JsonSubTypes.dll
 copy packages\RestSharp.105.1.0\lib\net45\RestSharp.dll bin\RestSharp.dll
-%CSCPATH%\csc  /reference:bin\Newtonsoft.Json.dll;bin\RestSharp.dll;System.ComponentModel.DataAnnotations.dll  /target:library /out:bin\IO.Swagger.dll /recurse:src\IO.Swagger\*.cs /doc:bin\IO.Swagger.xml
+%CSCPATH%\csc  /reference:bin\Newtonsoft.Json.dll;bin\JsonSubTypes.dll;bin\RestSharp.dll;System.ComponentModel.DataAnnotations.dll  /target:library /out:bin\IO.Swagger.dll /recurse:src\IO.Swagger\*.cs /doc:bin\IO.Swagger.xml
 
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/build.sh b/samples/client/petstore-security-test/csharp/SwaggerClient/build.sh
index 4892f3c07ea..5413cda4ddd 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/build.sh
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/build.sh
@@ -33,10 +33,10 @@ esac
 
 echo "[INFO] Target framework: ${frameworkVersion}"
 
-if [ ! type nuget &>/dev/null ]; then
+if ! type nuget &>/dev/null; then
     echo "[INFO] Download nuget and packages"
     wget -nc https://dist.nuget.org/win-x86-commandline/latest/nuget.exe;
-    nuget_cmd="mono nuget"
+    nuget_cmd="mono nuget.exe"
 fi
 
 mozroots --import --sync
@@ -46,9 +46,10 @@ echo "[INFO] Copy DLLs to the 'bin' folder"
 mkdir -p bin;
 cp packages/Newtonsoft.Json.10.0.3/lib/net45/Newtonsoft.Json.dll bin/Newtonsoft.Json.dll;
 cp packages/RestSharp.105.1.0/lib/net45/RestSharp.dll bin/RestSharp.dll;
+cp packages/JsonSubTypes.1.2.0/lib/net45/JsonSubTypes.dll bin/JsonSubTypes.dll
 
 echo "[INFO] Run 'mcs' to build bin/IO.Swagger.dll"
-mcs -langversion:${langversion} -sdk:${sdk} -r:bin/Newtonsoft.Json.dll,\
+mcs -langversion:${langversion} -sdk:${sdk} -r:bin/Newtonsoft.Json.dll,bin/JsonSubTypes.dll,\
 bin/RestSharp.dll,\
 System.ComponentModel.DataAnnotations.dll,\
 System.Runtime.Serialization.dll \
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/IO.Swagger.Test.csproj b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/IO.Swagger.Test.csproj
index 596b94b087d..67bd705cef4 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/IO.Swagger.Test.csproj
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/IO.Swagger.Test.csproj
@@ -53,10 +53,10 @@ Contact: apiteam@swagger.io *_/ ' \" =end - - \\r\\n \\n \\r
         <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\Newtonsoft.Json.10.0.3\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
     <Reference Include="JsonSubTypes">
-        <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-        <HintPath Condition="Exists('..\packages')">..\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-        <HintPath Condition="Exists('..\..\packages')">..\..\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-        <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
+        <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+        <HintPath Condition="Exists('..\packages')">..\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+        <HintPath Condition="Exists('..\..\packages')">..\..\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+        <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
     </Reference>
     <Reference Include="RestSharp">
         <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\RestSharp.105.1.0\lib\net45\RestSharp.dll</HintPath>
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/packages.config b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/packages.config
index a5a85c7294c..ac390c1dcb3 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/packages.config
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger.Test/packages.config
@@ -3,5 +3,5 @@
   <package id="NUnit" version="2.6.4" targetFramework="net45" />
   <package id="RestSharp" version="105.1.0" targetFramework="net45" developmentDependency="true" />
   <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net45" developmentDependency="true" />
-  <package id="JsonSubTypes" version="1.1.3" targetFramework="net45" developmentDependency="true" />
+  <package id="JsonSubTypes" version="1.2.0" targetFramework="net45" developmentDependency="true" />
 </packages>
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Client/ApiClient.cs b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Client/ApiClient.cs
index b5f0d4003b0..0a866ba9253 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Client/ApiClient.cs
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Client/ApiClient.cs
@@ -95,7 +95,7 @@ namespace IO.Swagger.Client
         /// <value>An instance of the IReadableConfiguration.</value>
         /// <remarks>
         /// <see cref="IReadableConfiguration"/> helps us to avoid modifying possibly global
-        /// configuration values from within a given client. It does not gaurantee thread-safety
+        /// configuration values from within a given client. It does not guarantee thread-safety
         /// of the <see cref="Configuration"/> instance in any way.
         /// </remarks>
         public IReadableConfiguration Configuration { get; set; }
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.csproj b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.csproj
index 27cd15d9106..62fe3f7ebd5 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.csproj
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.csproj
@@ -54,10 +54,10 @@ Contact: apiteam@swagger.io *_/ ' \" =end - - \\r\\n \\n \\r
       <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\Newtonsoft.Json.10.0.3\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
     <Reference Include="JsonSubTypes">
-      <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-      <HintPath Condition="Exists('..\packages')">..\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-      <HintPath Condition="Exists('..\..\packages')">..\..\packages\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
-      <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\JsonSubTypes.1.1.3\lib\net45\JsonSubTypes.dll</HintPath>
+      <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+      <HintPath Condition="Exists('..\packages')">..\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+      <HintPath Condition="Exists('..\..\packages')">..\..\packages\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
+      <HintPath Condition="Exists('..\..\vendor')">..\..\vendor\JsonSubTypes.1.2.0\lib\net45\JsonSubTypes.dll</HintPath>
     </Reference>
     <Reference Include="RestSharp">
         <HintPath Condition="Exists('$(SolutionDir)\packages')">$(SolutionDir)\packages\RestSharp.105.1.0\lib\net45\RestSharp.dll</HintPath>
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.nuspec b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.nuspec
index 5d0ad337e04..66e1c2e21ab 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.nuspec
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/IO.Swagger.nuspec
@@ -27,6 +27,7 @@
         <dependencies>
 
             <dependency id="NewtonSoft.Json" version="10.0.3" />
+            <dependency id="JsonSubTypes" version="1.2.0" />
             <dependency id="RestSharp" version="105.1.0" />
 
         </dependencies>
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
index e9e53a12799..e30ed66f4b6 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
@@ -63,7 +63,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/packages.config b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/packages.config
index 76a7cbd76d7..3caf34e0d76 100644
--- a/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/packages.config
+++ b/samples/client/petstore-security-test/csharp/SwaggerClient/src/IO.Swagger/packages.config
@@ -2,5 +2,5 @@
 <packages>
   <package id="RestSharp" version="105.1.0" targetFramework="net45" developmentDependency="true" />
   <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net45" developmentDependency="true" />
-  <package id="JsonSubTypes" version="1.1.3" targetFramework="net45" developmentDependency="true" />
+  <package id="JsonSubTypes" version="1.2.0" targetFramework="net45" developmentDependency="true" />
 </packages>
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/AdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
index ad54e625864..c11ae7e72f4 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ApiResponse.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ApiResponse.cs
index fc654b07f27..e4e7048711c 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ApiResponse.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ApiResponse.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
index 048483cdf48..24f51e9010e 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
index ccff9ee3f0e..44513c21762 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayTest.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayTest.cs
index 66cca739d5e..d6d3917a89d 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ArrayTest.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Capitalization.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Capitalization.cs
index b306023afd0..78af1207503 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Capitalization.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Capitalization.cs
@@ -108,7 +108,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Category.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Category.cs
index c2a3462cf99..af12c8c3b39 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Category.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Category.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ClassModel.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ClassModel.cs
index 4d00dbef97b..cccdd843f00 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ClassModel.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ClassModel.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumArrays.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumArrays.cs
index e5fd519b943..7b5b206889f 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumArrays.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumArrays.cs
@@ -112,7 +112,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumTest.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumTest.cs
index 310979af1e5..df4ebc66c81 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/EnumTest.cs
@@ -154,7 +154,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/FormatTest.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/FormatTest.cs
index f651fbf5d5e..25e6c7925f3 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/FormatTest.cs
@@ -208,7 +208,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/HasOnlyReadOnly.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/HasOnlyReadOnly.cs
index 8c15b451b1f..e0510de72db 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/HasOnlyReadOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/HasOnlyReadOnly.cs
@@ -68,7 +68,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/List.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/List.cs
index 52a234d8cd5..eb3f6dacfe2 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/List.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/List.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MapTest.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MapTest.cs
index 4b99b4ab67f..e68482ececc 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MapTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MapTest.cs
@@ -92,7 +92,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index fb0a3998053..ff71e5b3d5b 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Model200Response.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Model200Response.cs
index 3d11d1188eb..71b4d96c871 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Model200Response.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Model200Response.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelClient.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelClient.cs
index 5184c5c33d2..a01c9487ce6 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelClient.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
index 9d885bdff8a..412c676a8ad 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ModelReturn.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Name.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Name.cs
index d4c149c0fad..31c8e25bcd1 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Name.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Name.cs
@@ -98,7 +98,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/NumberOnly.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/NumberOnly.cs
index 61c9be60c1d..27f1522e63d 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/NumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/NumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Order.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Order.cs
index 87c6df4891c..c8bddf3c33e 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Order.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Order.cs
@@ -143,7 +143,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterBoolean.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterBoolean.cs
index 45a3382919f..a848353fcde 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterBoolean.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterBoolean.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterComposite.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterComposite.cs
index 4c12290c2ee..5b14554b643 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterComposite.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterComposite.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterNumber.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterNumber.cs
index 395239a27c1..5b52454df7d 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterNumber.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterNumber.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterString.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterString.cs
index 4a08ab3f7f7..9c025c0d38b 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterString.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/OuterString.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Pet.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Pet.cs
index 1512b607384..c218ecd4840 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Pet.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Pet.cs
@@ -156,7 +156,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ReadOnlyFirst.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ReadOnlyFirst.cs
index fa281fdecf7..af7030e59a3 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ReadOnlyFirst.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/ReadOnlyFirst.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/SpecialModelName.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/SpecialModelName.cs
index 198a04fee71..177e401ec96 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/SpecialModelName.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/SpecialModelName.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Tag.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Tag.cs
index a4ae373b979..4ad09373c43 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Tag.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/Tag.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/User.cs b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/User.cs
index ada8d682356..773882600b3 100644
--- a/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/User.cs
+++ b/samples/client/petstore/csharp/SwaggerClient/src/IO.Swagger/Model/User.cs
@@ -126,7 +126,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/AdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
index e383303aa59..271cfba5d5e 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ApiResponse.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ApiResponse.cs
index e3ecff719d5..e8d0570cb7e 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ApiResponse.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ApiResponse.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
index f0136b6987e..4badc3bd44c 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
index 5582c3f95aa..41b7d2af821 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayTest.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayTest.cs
index 277d0f2f3cf..d58f2cc51b3 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ArrayTest.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Capitalization.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Capitalization.cs
index 65ad50cbcc3..d48b618b27a 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Capitalization.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Capitalization.cs
@@ -108,7 +108,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Category.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Category.cs
index ab0b97d571c..6b98cae97bd 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Category.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Category.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ClassModel.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ClassModel.cs
index 59c49c63206..cf9f0eed3d2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ClassModel.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ClassModel.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumArrays.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumArrays.cs
index 3ba1af726e2..eec89794289 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumArrays.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumArrays.cs
@@ -112,7 +112,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumTest.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumTest.cs
index 7ac454f9308..9e4f6a56b62 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/EnumTest.cs
@@ -154,7 +154,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/FormatTest.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/FormatTest.cs
index 16c06090cd5..9d8c1997523 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/FormatTest.cs
@@ -208,7 +208,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/HasOnlyReadOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/HasOnlyReadOnly.cs
index eded5814402..14b9e089c8d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/HasOnlyReadOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/HasOnlyReadOnly.cs
@@ -68,7 +68,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/List.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/List.cs
index a7a1e617f89..3c18bb2bcb8 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/List.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/List.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MapTest.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MapTest.cs
index 9115fab4cfe..3b6655b284b 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MapTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MapTest.cs
@@ -92,7 +92,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 58cabfb955f..3d4b0ed66d2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Model200Response.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Model200Response.cs
index 1f3821ec104..331923b20ff 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Model200Response.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Model200Response.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelClient.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelClient.cs
index 7b37ced08a0..a971e66e192 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelClient.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelReturn.cs
index 5f47de2fd2c..6a7c8289dbd 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ModelReturn.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Name.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Name.cs
index c46ad200a3e..4e9e284aea6 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Name.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Name.cs
@@ -98,7 +98,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/NumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/NumberOnly.cs
index edbeff5d980..d238193aa8f 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/NumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/NumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Order.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Order.cs
index 5de8659b066..a800f2e11f4 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Order.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Order.cs
@@ -143,7 +143,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterBoolean.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterBoolean.cs
index f6acd91a71f..43154215b9d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterBoolean.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterBoolean.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterComposite.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterComposite.cs
index 726a495327f..f29a8e55202 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterComposite.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterComposite.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterNumber.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterNumber.cs
index abc86534769..83e4d0a42cc 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterNumber.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterNumber.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterString.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterString.cs
index 1623301f593..81b9219113e 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterString.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/OuterString.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Pet.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Pet.cs
index 7efdaa89511..12c1937f9bf 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Pet.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Pet.cs
@@ -156,7 +156,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ReadOnlyFirst.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ReadOnlyFirst.cs
index 2f8063b96bc..cf8176592f6 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ReadOnlyFirst.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/ReadOnlyFirst.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/SpecialModelName.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/SpecialModelName.cs
index aedc53b9999..b103d5e6144 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/SpecialModelName.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/SpecialModelName.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Tag.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Tag.cs
index 16217828230..d21e67778dd 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Tag.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/Tag.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/User.cs b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/User.cs
index b43e0b4efc7..584ec8c310d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/User.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet35/src/IO.Swagger/Model/User.cs
@@ -126,7 +126,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/AdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
index ad54e625864..c11ae7e72f4 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ApiResponse.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ApiResponse.cs
index fc654b07f27..e4e7048711c 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ApiResponse.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ApiResponse.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
index 048483cdf48..24f51e9010e 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
index ccff9ee3f0e..44513c21762 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayTest.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayTest.cs
index 66cca739d5e..d6d3917a89d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ArrayTest.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Capitalization.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Capitalization.cs
index b306023afd0..78af1207503 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Capitalization.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Capitalization.cs
@@ -108,7 +108,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Category.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Category.cs
index c2a3462cf99..af12c8c3b39 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Category.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Category.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ClassModel.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ClassModel.cs
index 4d00dbef97b..cccdd843f00 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ClassModel.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ClassModel.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumArrays.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumArrays.cs
index e5fd519b943..7b5b206889f 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumArrays.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumArrays.cs
@@ -112,7 +112,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumTest.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumTest.cs
index 310979af1e5..df4ebc66c81 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/EnumTest.cs
@@ -154,7 +154,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/FormatTest.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/FormatTest.cs
index f651fbf5d5e..25e6c7925f3 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/FormatTest.cs
@@ -208,7 +208,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/HasOnlyReadOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/HasOnlyReadOnly.cs
index 8c15b451b1f..e0510de72db 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/HasOnlyReadOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/HasOnlyReadOnly.cs
@@ -68,7 +68,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/List.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/List.cs
index 52a234d8cd5..eb3f6dacfe2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/List.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/List.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MapTest.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MapTest.cs
index 4b99b4ab67f..e68482ececc 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MapTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MapTest.cs
@@ -92,7 +92,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index fb0a3998053..ff71e5b3d5b 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Model200Response.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Model200Response.cs
index 3d11d1188eb..71b4d96c871 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Model200Response.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Model200Response.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelClient.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelClient.cs
index 5184c5c33d2..a01c9487ce6 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelClient.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelReturn.cs
index 9d885bdff8a..412c676a8ad 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ModelReturn.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Name.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Name.cs
index d4c149c0fad..31c8e25bcd1 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Name.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Name.cs
@@ -98,7 +98,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/NumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/NumberOnly.cs
index 61c9be60c1d..27f1522e63d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/NumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/NumberOnly.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Order.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Order.cs
index 87c6df4891c..c8bddf3c33e 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Order.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Order.cs
@@ -143,7 +143,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterBoolean.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterBoolean.cs
index 45a3382919f..a848353fcde 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterBoolean.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterBoolean.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterComposite.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterComposite.cs
index 4c12290c2ee..5b14554b643 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterComposite.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterComposite.cs
@@ -80,7 +80,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterNumber.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterNumber.cs
index 395239a27c1..5b52454df7d 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterNumber.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterNumber.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterString.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterString.cs
index 4a08ab3f7f7..9c025c0d38b 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterString.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/OuterString.cs
@@ -54,7 +54,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Pet.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Pet.cs
index 1512b607384..c218ecd4840 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Pet.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Pet.cs
@@ -156,7 +156,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ReadOnlyFirst.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ReadOnlyFirst.cs
index fa281fdecf7..af7030e59a3 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ReadOnlyFirst.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/ReadOnlyFirst.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/SpecialModelName.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/SpecialModelName.cs
index 198a04fee71..177e401ec96 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/SpecialModelName.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/SpecialModelName.cs
@@ -62,7 +62,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Tag.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Tag.cs
index a4ae373b979..4ad09373c43 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Tag.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/Tag.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/User.cs b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/User.cs
index ada8d682356..773882600b3 100644
--- a/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/User.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNet40/src/IO.Swagger/Model/User.cs
@@ -126,7 +126,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/AdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
index 879bb7fcede..51b5d86bf47 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ApiResponse.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ApiResponse.cs
index 8782c39aee2..5e03eeda044 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ApiResponse.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ApiResponse.cs
@@ -78,7 +78,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
index 011c403f455..f2202240e70 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
index fe3f3f2fa86..ab2deba2484 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayTest.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayTest.cs
index f1e32b23b9c..992dc11e15b 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ArrayTest.cs
@@ -78,7 +78,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Capitalization.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Capitalization.cs
index e4a61efdd45..69794a2be1a 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Capitalization.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Capitalization.cs
@@ -106,7 +106,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Category.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Category.cs
index 09cee2182e2..1d553e47109 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Category.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Category.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ClassModel.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ClassModel.cs
index db91a825dc2..3fcff106b2a 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ClassModel.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ClassModel.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumArrays.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumArrays.cs
index 3280ae94b5f..5391fb4a8e2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumArrays.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumArrays.cs
@@ -110,7 +110,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumTest.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumTest.cs
index f32e7fec942..d734025d483 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/EnumTest.cs
@@ -152,7 +152,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/FormatTest.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/FormatTest.cs
index 3cbb1b86eff..6ea25d953f0 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/FormatTest.cs
@@ -206,7 +206,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/HasOnlyReadOnly.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/HasOnlyReadOnly.cs
index 9eca2f0d5af..e19333c9aff 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/HasOnlyReadOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/HasOnlyReadOnly.cs
@@ -66,7 +66,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/List.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/List.cs
index 37cbae79e1a..8e584d1d945 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/List.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/List.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MapTest.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MapTest.cs
index 09ddd6e0936..7563ad74afa 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MapTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MapTest.cs
@@ -90,7 +90,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index 3fa6f8d7d2f..15ac5cd269c 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -78,7 +78,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Model200Response.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Model200Response.cs
index f4647201c72..1a6eb33e334 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Model200Response.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Model200Response.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelClient.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelClient.cs
index 863a2a438d1..13f8f0cff52 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelClient.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelReturn.cs
index 0e031e3ee47..2373b968ea2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ModelReturn.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Name.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Name.cs
index cece286486f..ac996069e08 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Name.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Name.cs
@@ -96,7 +96,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/NumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/NumberOnly.cs
index 7736b087c7b..3c3e83b2262 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/NumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/NumberOnly.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Order.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Order.cs
index 7bf0d935007..3d2c54c6556 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Order.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Order.cs
@@ -141,7 +141,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterBoolean.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterBoolean.cs
index 72368984bb8..86775e830e1 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterBoolean.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterBoolean.cs
@@ -52,7 +52,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterComposite.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterComposite.cs
index 084db10819a..46fbc5e21b2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterComposite.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterComposite.cs
@@ -78,7 +78,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterNumber.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterNumber.cs
index a9317a3a9f3..4cb2f0053d2 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterNumber.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterNumber.cs
@@ -52,7 +52,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterString.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterString.cs
index 3b7c5e6c931..8a9baf94a94 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterString.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/OuterString.cs
@@ -52,7 +52,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Pet.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Pet.cs
index eabf982b680..3f1ae834393 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Pet.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Pet.cs
@@ -154,7 +154,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ReadOnlyFirst.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ReadOnlyFirst.cs
index 73e33ae3d4f..2565a394a73 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ReadOnlyFirst.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/ReadOnlyFirst.cs
@@ -67,7 +67,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/SpecialModelName.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/SpecialModelName.cs
index 5f412aa1135..865845c329a 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/SpecialModelName.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/SpecialModelName.cs
@@ -60,7 +60,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Tag.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Tag.cs
index 0207cb981f0..45aa6818bd1 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Tag.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/Tag.cs
@@ -69,7 +69,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/User.cs b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/User.cs
index c56c8cd1aa0..30c411ed952 100644
--- a/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/User.cs
+++ b/samples/client/petstore/csharp/SwaggerClientNetStandard/src/IO.Swagger/Model/User.cs
@@ -124,7 +124,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/AdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
index 12d2321845a..39b40dad938 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/AdditionalPropertiesClass.cs
@@ -74,7 +74,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ApiResponse.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ApiResponse.cs
index ef6b5c3e183..9e6f328dec7 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ApiResponse.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ApiResponse.cs
@@ -83,7 +83,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
index f7d7fd178fe..b576f5e980c 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfArrayOfNumberOnly.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfNumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
index 72022dfff14..f6dfc3d3c3e 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayOfNumberOnly.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayTest.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayTest.cs
index 64473d4d14f..4cc97026da2 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ArrayTest.cs
@@ -83,7 +83,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Capitalization.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Capitalization.cs
index fa6332b281f..09b2b86102d 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Capitalization.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Capitalization.cs
@@ -111,7 +111,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Category.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Category.cs
index 5208f032169..87b93ebb81c 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Category.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Category.cs
@@ -74,7 +74,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ClassModel.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ClassModel.cs
index 8b017f9d707..e45f78059b2 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ClassModel.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ClassModel.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumArrays.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumArrays.cs
index 0b99744d338..3f408068bad 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumArrays.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumArrays.cs
@@ -115,7 +115,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumTest.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumTest.cs
index 542f4ea6791..846dd43ab51 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/EnumTest.cs
@@ -157,7 +157,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/FormatTest.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/FormatTest.cs
index bed68002142..2671ccea2d0 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/FormatTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/FormatTest.cs
@@ -211,7 +211,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/HasOnlyReadOnly.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/HasOnlyReadOnly.cs
index 87982185d61..6f2a7e0da58 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/HasOnlyReadOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/HasOnlyReadOnly.cs
@@ -71,7 +71,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/List.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/List.cs
index a6f5a1ce908..6c76124c23a 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/List.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/List.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MapTest.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MapTest.cs
index 7ca40df5a21..7ab7098dc8f 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MapTest.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MapTest.cs
@@ -95,7 +95,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
index ac512031cb2..d69f7f54a7a 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/MixedPropertiesAndAdditionalPropertiesClass.cs
@@ -83,7 +83,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Model200Response.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Model200Response.cs
index 91cbb36fe01..5e61f28fec2 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Model200Response.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Model200Response.cs
@@ -74,7 +74,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelClient.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelClient.cs
index a786c496c65..bd959a8a26c 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelClient.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelClient.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelReturn.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelReturn.cs
index 1e5804872b9..d7de61fb4aa 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelReturn.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ModelReturn.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Name.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Name.cs
index f38f5ba70ed..ce4fa8672d9 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Name.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Name.cs
@@ -101,7 +101,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/NumberOnly.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/NumberOnly.cs
index bc50ca2aa7b..ce574d1945d 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/NumberOnly.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/NumberOnly.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Order.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Order.cs
index 6c0311fb6d1..f7da8aa6862 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Order.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Order.cs
@@ -146,7 +146,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterBoolean.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterBoolean.cs
index 422b1864477..2b3eab3b13a 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterBoolean.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterBoolean.cs
@@ -57,7 +57,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterComposite.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterComposite.cs
index 4a4deedcf6e..bba9945febb 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterComposite.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterComposite.cs
@@ -83,7 +83,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterNumber.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterNumber.cs
index 275f1fb0988..efdca1968e2 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterNumber.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterNumber.cs
@@ -57,7 +57,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterString.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterString.cs
index 570b8e872fd..7f412704f52 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterString.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/OuterString.cs
@@ -57,7 +57,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Pet.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Pet.cs
index 1a659b7412b..f44ebee2ef8 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Pet.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Pet.cs
@@ -159,7 +159,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ReadOnlyFirst.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ReadOnlyFirst.cs
index 74d416fc8c8..f65a429bb07 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ReadOnlyFirst.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/ReadOnlyFirst.cs
@@ -72,7 +72,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/SpecialModelName.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/SpecialModelName.cs
index 8de75641544..b7756fa21bd 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/SpecialModelName.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/SpecialModelName.cs
@@ -65,7 +65,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Tag.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Tag.cs
index 632a7558bcc..f47899d1130 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Tag.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/Tag.cs
@@ -74,7 +74,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }
diff --git a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/User.cs b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/User.cs
index 2aa51053e4f..f815c1c0803 100644
--- a/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/User.cs
+++ b/samples/client/petstore/csharp/SwaggerClientWithPropertyChanged/src/IO.Swagger/Model/User.cs
@@ -129,7 +129,7 @@ namespace IO.Swagger.Model
         /// Returns the JSON string presentation of the object
         /// </summary>
         /// <returns>JSON string presentation of the object</returns>
-        public string ToJson()
+        public virtual string ToJson()
         {
             return JsonConvert.SerializeObject(this, Formatting.Indented);
         }