diff --git a/CI/pom.xml.shippable b/CI/pom.xml.shippable
index fbb649dba90..fb626b474b6 100644
--- a/CI/pom.xml.shippable
+++ b/CI/pom.xml.shippable
@@ -120,7 +120,7 @@
                         <id>validate</id>
                         <phase>validate</phase>
                         <configuration>
-                            <configLocation>google_checkstyle.xml</configLocation>
+                            <configLocation>../google_checkstyle.xml</configLocation>
                             <!-- Don't include generated sources a la http://stackoverflow.com/a/30406454 -->
                             <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
                             <encoding>UTF-8</encoding>
@@ -355,7 +355,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/android/volley</module>
+                <module>../samples/client/petstore/android/volley</module>
             </modules>
         </profile>
         <profile>
@@ -367,7 +367,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/bash</module>
+                <module>../samples/client/petstore/bash</module>
             </modules>
         </profile>
         <profile>
@@ -379,7 +379,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/clojure</module>
+                <module>../samples/client/petstore/clojure</module>
             </modules>
         </profile>
         <profile>
@@ -391,7 +391,7 @@
                 </property>
             </activation>
             <modules>
-                <!--<module>samples/client/petstore/haskell-http-client</module>-->
+                <!--<module>../samples/client/petstore/haskell-http-client</module>-->
             </modules>
         </profile>
         <profile>
@@ -403,7 +403,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/haskell-http-client/tests-integration</module>
+                <module>../samples/client/petstore/haskell-http-client/tests-integration</module>
             </modules>
         </profile>
         <profile>
@@ -415,7 +415,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/jersey1</module>
+                <module>../samples/client/petstore/java/jersey1</module>
             </modules>
         </profile>
         <profile>
@@ -427,7 +427,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/jersey2</module>
+                <module>../samples/client/petstore/java/jersey2</module>
             </modules>
         </profile>
         <profile>
@@ -439,7 +439,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/jersey2-java6</module>
+                <module>../samples/client/petstore/java/jersey2-java6</module>
             </modules>
         </profile>
         <profile>
@@ -451,7 +451,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/okhttp-gson</module>
+                <module>../samples/client/petstore/java/okhttp-gson</module>
             </modules>
         </profile>
         <profile>
@@ -463,7 +463,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/okhttp-gson/parcelableModel</module>
+                <module>../samples/client/petstore/java/okhttp-gson/parcelableModel</module>
             </modules>
         </profile>
         <profile>
@@ -475,7 +475,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/retrofit</module>
+                <module>../samples/client/petstore/java/retrofit</module>
             </modules>
         </profile>
         <profile>
@@ -487,7 +487,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/retrofit2</module>
+                <module>../samples/client/petstore/java/retrofit2</module>
             </modules>
         </profile>
         <profile>
@@ -499,7 +499,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/retrofit2rx</module>
+                <module>../samples/client/petstore/java/retrofit2rx</module>
             </modules>
         </profile>
         <profile>
@@ -511,7 +511,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/java/feign</module>
+                <module>../samples/client/petstore/java/feign</module>
             </modules>
         </profile>
         <profile>
@@ -523,7 +523,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/javascript</module>
+                <module>../samples/client/petstore/javascript</module>
             </modules>
         </profile>
         <profile>
@@ -535,7 +535,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/scala</module>
+                <module>../samples/client/petstore/scala</module>
             </modules>
         </profile>
         <profile>
@@ -547,7 +547,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/java-msf4/</module>
+                <module>../samples/server/petstore/java-msf4/</module>
             </modules>
         </profile>
         <profile>
@@ -559,7 +559,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs-cxf</module>
+                <module>../samples/server/petstore/jaxrs-cxf</module>
             </modules>
         </profile>
         <profile>
@@ -571,7 +571,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs-resteasy/default</module>
+                <module>../samples/server/petstore/jaxrs-resteasy/default</module>
             </modules>
         </profile>
         <profile>
@@ -583,7 +583,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs-resteasy/joda</module>
+                <module>../samples/server/petstore/jaxrs-resteasy/joda</module>
             </modules>
         </profile>
         <profile>
@@ -595,7 +595,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs-resteasy/eap</module>
+                <module>../samples/server/petstore/jaxrs-resteasy/eap</module>
             </modules>
         </profile>
         <profile>
@@ -607,7 +607,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs-resteasy/eap-joda</module>
+                <module>../samples/server/petstore/jaxrs-resteasy/eap-joda</module>
             </modules>
         </profile>
         <profile>
@@ -619,7 +619,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs/jersey2</module>
+                <module>../samples/server/petstore/jaxrs/jersey2</module>
             </modules>
         </profile>
         <profile>
@@ -631,7 +631,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/jaxrs/jersey1</module>
+                <module>../samples/server/petstore/jaxrs/jersey1</module>
             </modules>
         </profile>
         <profile>
@@ -643,7 +643,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-fetch/tests/default</module>
+                <module>../samples/client/petstore/typescript-fetch/tests/default</module>
             </modules>
         </profile>
         <profile>
@@ -655,7 +655,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-fetch/builds/default</module>
+                <module>../samples/client/petstore/typescript-fetch/builds/default</module>
             </modules>
         </profile>
         <profile>
@@ -667,7 +667,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-fetch/builds/es6-target</module>
+                <module>../samples/client/petstore/typescript-fetch/builds/es6-target</module>
             </modules>
         </profile>
         <profile>
@@ -679,7 +679,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-fetch/builds/with-npm-version</module>
+                <module>../samples/client/petstore/typescript-fetch/builds/with-npm-version</module>
             </modules>
         </profile>
         <profile>
@@ -691,7 +691,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-angularjs/npm</module>
+                <module>../samples/client/petstore/typescript-angularjs/npm</module>
             </modules>
         </profile>
         <profile>
@@ -703,7 +703,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/typescript-node/npm</module>
+                <module>../samples/client/petstore/typescript-node/npm</module>
             </modules>
         </profile>
         <profile>
@@ -715,7 +715,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/python</module>
+                <module>../samples/client/petstore/python</module>
             </modules>
         </profile>
         <profile>
@@ -727,7 +727,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/ruby</module>
+                <module>../samples/client/petstore/ruby</module>
             </modules>
         </profile>
         <profile>
@@ -739,7 +739,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/go</module>
+                <module>../samples/client/petstore/go</module>
             </modules>
         </profile>
         <profile>
@@ -751,7 +751,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/spring-mvc</module>
+                <module>../samples/server/petstore/spring-mvc</module>
             </modules>
         </profile>
         <profile>
@@ -763,7 +763,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/springboot-beanvalidation</module>
+                <module>../samples/server/petstore/springboot-beanvalidation</module>
             </modules>
         </profile>
         <profile>
@@ -775,7 +775,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/springboot-reactive</module>
+                <module>../samples/server/petstore/springboot-reactive</module>
             </modules>
         </profile>
         <profile>
@@ -787,7 +787,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/springboot</module>
+                <module>../samples/server/petstore/springboot</module>
             </modules>
         </profile>
         <profile>
@@ -799,7 +799,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/client/petstore/spring-cloud</module>
+                <module>../samples/client/petstore/spring-cloud</module>
             </modules>
         </profile>
         <profile>
@@ -811,7 +811,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/scalatra</module>
+                <module>../samples/server/petstore/scalatra</module>
             </modules>
         </profile>
         <profile>
@@ -823,7 +823,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/java-inflector</module>
+                <module>../samples/server/petstore/java-inflector</module>
             </modules>
         </profile>
         <profile>
@@ -835,7 +835,7 @@
                 </property>
             </activation>
             <modules>
-                <module>samples/server/petstore/undertow</module>
+                <module>../samples/server/petstore/undertow</module>
             </modules>
         </profile>
         <profile>
@@ -848,19 +848,19 @@
             </activation>
             <modules>
                 <!-- clients -->
-                <module>samples/client/petstore/elixir</module>
-                <!--<module>samples/client/petstore/haskell-http-client</module>-->
-                <module>samples/client/petstore/erlang-client</module>
+                <module>../samples/client/petstore/elixir</module>
+                <!--<module>../samples/client/petstore/haskell-http-client</module>-->
+                <module>../samples/client/petstore/erlang-client</module>
                 <!-- servers -->
-                <module>samples/server/petstore/erlang-server</module>
+                <module>../samples/server/petstore/erlang-server</module>
             </modules>
         </profile>
     </profiles>
     <modules>
-        <module>modules/openapi-generator</module>
-        <module>modules/openapi-generator-cli</module>
-        <module>modules/openapi-generator-maven-plugin</module>
-        <module>modules/openapi-generator-online</module>
+        <module>../modules/openapi-generator</module>
+        <module>../modules/openapi-generator-cli</module>
+        <module>../modules/openapi-generator-maven-plugin</module>
+        <module>../modules/openapi-generator-online</module>
     </modules>
     <reporting>
         <outputDirectory>target/site</outputDirectory>
diff --git a/bin/ensure-up-to-date b/bin/ensure-up-to-date
new file mode 100755
index 00000000000..3149e93c075
--- /dev/null
+++ b/bin/ensure-up-to-date
@@ -0,0 +1,30 @@
+#!/bin/bash
+# this bash script run the scripts for the 'mature' generators
+# it ensures that all changes are commited into the 'samples/' folder
+
+echo "# START SCRIPT: $0"
+
+echo "IMPORTANT: this script should be run by the CI (e.g. Shippable) to ensure that the 'samples/' folder is up to date."
+echo "Please press CTRL+C to stop or the script will continue in 5 seconds."
+
+sleep 5
+
+# LIST OF SCRIPTS:
+./bin/ruby-petstore.sh
+./bin/java-petstore-all.sh
+./bin/spring-all-pestore.sh
+./bin/kotlin-client-petstore.sh
+./bin/kotlin-client-string.sh
+./bin/kotlin-client-threetenbp.sh
+./bin/kotlin-server-petstore.sh
+
+# Check:
+if [ -n "$(git status --porcelain)" ]; then
+    echo "UNCOMMITTED CHANGES ERROR"
+    echo "There are uncommitted changes in working tree after execution of 'bin/ensure-up-to-date'"
+    git status
+    echo "Please run 'bin/ensure-up-to-date' locally and commit changes"
+    exit 1
+else
+    echo "Git working tree is clean"
+fi
diff --git a/samples/client/petstore/kotlin/README.md b/samples/client/petstore/kotlin/README.md
index ffc358aac7c..b9ab400b15e 100644
--- a/samples/client/petstore/kotlin/README.md
+++ b/samples/client/petstore/kotlin/README.md
@@ -63,6 +63,7 @@ Class | Method | HTTP request | Description
  - [org.openapitools.client.models.ApiResponse](docs/ApiResponse.md)
  - [org.openapitools.client.models.Category](docs/Category.md)
  - [org.openapitools.client.models.Order](docs/Order.md)
+ - [org.openapitools.client.models.Pet](docs/Pet.md)
  - [org.openapitools.client.models.Tag](docs/Tag.md)
  - [org.openapitools.client.models.User](docs/User.md)
 
diff --git a/samples/client/petstore/ruby/docs/FakeApi.md b/samples/client/petstore/ruby/docs/FakeApi.md
index a1bd0f2f908..01b3aac12ac 100644
--- a/samples/client/petstore/ruby/docs/FakeApi.md
+++ b/samples/client/petstore/ruby/docs/FakeApi.md
@@ -408,7 +408,7 @@ Name | Type | Description  | Notes
  **enum_query_string** | **String**| Query parameter enum test (string) | [optional] [default to &#39;-efg&#39;]
  **enum_query_integer** | **Integer**| Query parameter enum test (double) | [optional] 
  **enum_query_double** | **Float**| Query parameter enum test (double) | [optional] 
- **enum_form_string_array** | **Array&lt;String&gt;**| Form parameter enum test (string array) | [optional] [default to &#39;$&#39;]
+ **enum_form_string_array** | [**Array&lt;String&gt;**](String.md)| Form parameter enum test (string array) | [optional] [default to &#39;$&#39;]
  **enum_form_string** | **String**| Form parameter enum test (string) | [optional] [default to &#39;-efg&#39;]
 
 ### Return type
diff --git a/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Order.kt b/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Order.kt
index 83dc98d1cdd..3ec31bfc714 100644
--- a/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Order.kt
+++ b/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Order.kt
@@ -35,7 +35,7 @@ data class Order (
     * Order Status
     * Values: placed,approved,delivered
     */
-    enum class Status(val value: kotlin.Any){
+    enum class Status(val value: kotlin.String){
     
         placed("placed"),
     
diff --git a/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Pet.kt b/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Pet.kt
index 8c00a67d729..45dfb4df12b 100644
--- a/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Pet.kt
+++ b/samples/server/petstore/kotlin-server/ktor/src/main/kotlin/org/openapitools/server/models/Pet.kt
@@ -37,7 +37,7 @@ data class Pet (
     * pet status in the store
     * Values: available,pending,sold
     */
-    enum class Status(val value: kotlin.Any){
+    enum class Status(val value: kotlin.String){
     
         available("available"),
     
diff --git a/shippable.yml b/shippable.yml
index 9426489257a..56aa70e09c6 100644
--- a/shippable.yml
+++ b/shippable.yml
@@ -10,6 +10,10 @@ build:
     - $HOME/.stack
     - $SHIPPABLE_REPO_DIR/samples/client/petstore/elixir/deps
   ci:
+    - mvn --quiet clean install -f CI/pom.xml.shippable
+    # ensure all modifications created by 'mature' generators are in the git repo
+    - ./bin/ensure-up-to-date
+    # prepare enviroment for tests
     - sudo apt-get update -qq
     # install stack
     - curl -sSL https://get.haskellstack.org/ | sh
@@ -27,10 +31,6 @@ build:
     - elixir --version
     - mix --version
     # test samples defined in pom.xml
-    - cp CI/pom.xml.shippable pom.xml
-    - mvn --quiet clean install
-    - mvn --quiet verify -P samples
-    # generate all petstore sampless (client, servers, doc)
-    - ./bin/run-all-petstore 2>&1 > run-all-petstore.log
-  post_ci:
-    - tail run-all-petstore.log
+    - mvn --quiet verify -P samples -f CI/pom.xml.shippable
+    # generate all petstore samples (client, servers, doc)
+    - ./bin/run-all-petstore