diff --git a/bin/configs/csharp-netcore-OpenAPIClient-httpclient.yaml b/bin/configs/csharp-netcore-OpenAPIClient-httpclient.yaml
index 21fba7e257a..a716aec5267 100644
--- a/bin/configs/csharp-netcore-OpenAPIClient-httpclient.yaml
+++ b/bin/configs/csharp-netcore-OpenAPIClient-httpclient.yaml
@@ -9,4 +9,4 @@ additionalProperties:
   useCompareNetObjects: true 
   disallowAdditionalPropertiesIfNotPresent: false
   useOneOfDiscriminatorLookup: true
-  targetFramework: netstandard2.1
+  targetFramework: netstandard2.0
diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/libraries/httpclient/ApiClient.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/libraries/httpclient/ApiClient.mustache
index ad2ca7ce4b5..4c31f4e127b 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/libraries/httpclient/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/libraries/httpclient/ApiClient.mustache
@@ -319,7 +319,7 @@ namespace {{packageName}}.Client
                 {
                     if (options.Data is Stream s)
                     {
-                        contentType ??= "application/octet-stream";
+                        contentType = contentType ?? "application/octet-stream";
 
                         var streamContent = new StreamContent(s);
                         streamContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Client/ApiClient.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Client/ApiClient.cs
index 60ba4090776..43dba569483 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Client/ApiClient.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Client/ApiClient.cs
@@ -305,7 +305,7 @@ namespace Org.OpenAPITools.Client
                 {
                     if (options.Data is Stream s)
                     {
-                        contentType ??= "application/octet-stream";
+                        contentType = contentType ?? "application/octet-stream";
 
                         var streamContent = new StreamContent(s);
                         streamContent.Headers.ContentType = new MediaTypeHeaderValue(contentType);
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Org.OpenAPITools.csproj b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Org.OpenAPITools.csproj
index c415e6768bc..254cb0c9fc2 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Org.OpenAPITools.csproj
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Org.OpenAPITools.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
-    <TargetFramework>netstandard2.1</TargetFramework>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <AssemblyName>Org.OpenAPITools</AssemblyName>
     <PackageId>Org.OpenAPITools</PackageId>
     <OutputType>Library</OutputType>