diff --git a/appveyor.yml b/appveyor.yml
index 452ce09918daa3d9b2508121ee10ecce3ac803d4..24610d9100eb48f9c36b8f040fe901a3124e7f03 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -35,6 +35,12 @@ install:
   - ps: Install-Module Pester -Force -Scope CurrentUser
 build_script:
   - dotnet --info
+  # build C# aspnetcore 3.1 server
+  - dotnet build samples\server\petstore\aspnetcore-3.1\Org.OpenAPITools.sln
+  # build C# aspnetcore 3.0 server
+  - dotnet build samples\server\petstore\aspnetcore-3.0\Org.OpenAPITools.sln
+  # build C# aspnetcore 2.2 server
+  - dotnet build samples\server\petstore\aspnetcore\Org.OpenAPITools.sln
   # build C# API client (netcore)
   - dotnet build samples\client\petstore\csharp-netcore\OpenAPIClient\Org.OpenAPITools.sln
   - dotnet build samples\client\petstore\csharp-netcore\OpenAPIClientCore\Org.OpenAPITools.sln
diff --git a/bin/configs/other/aspnetcore-3.0.yaml b/bin/configs/aspnetcore-3.0.yaml
similarity index 100%
rename from bin/configs/other/aspnetcore-3.0.yaml
rename to bin/configs/aspnetcore-3.0.yaml
diff --git a/bin/configs/other/aspnetcore-3.1.yaml b/bin/configs/aspnetcore-3.1.yaml
similarity index 100%
rename from bin/configs/other/aspnetcore-3.1.yaml
rename to bin/configs/aspnetcore-3.1.yaml
diff --git a/bin/configs/other/aspnetcore.yaml b/bin/configs/aspnetcore.yaml
similarity index 100%
rename from bin/configs/other/aspnetcore.yaml
rename to bin/configs/aspnetcore.yaml
diff --git a/samples/server/petstore/aspnetcore-3.0/.openapi-generator-ignore b/samples/server/petstore/aspnetcore-3.0/.openapi-generator-ignore
index 7484ee590a3894506cf063799b885428f95a71be..2832abc181293f78f1f940458904529b7eaa7ea3 100644
--- a/samples/server/petstore/aspnetcore-3.0/.openapi-generator-ignore
+++ b/samples/server/petstore/aspnetcore-3.0/.openapi-generator-ignore
@@ -21,3 +21,4 @@
 #docs/*.md
 # Then explicitly reverse the ignore rule for a single file:
 #!docs/README.md
+src/Org.OpenAPITools/Org.OpenAPITools.csproj
diff --git a/samples/server/petstore/aspnetcore-3.0/.openapi-generator/FILES b/samples/server/petstore/aspnetcore-3.0/.openapi-generator/FILES
index 4de0e6417904d60e1babca0314a21976b4db0392..f39431847dff16308121e7bc84dfc8d59cdbd1ed 100644
--- a/samples/server/petstore/aspnetcore-3.0/.openapi-generator/FILES
+++ b/samples/server/petstore/aspnetcore-3.0/.openapi-generator/FILES
@@ -19,7 +19,6 @@ src/Org.OpenAPITools/Models/Pet.cs
 src/Org.OpenAPITools/Models/Tag.cs
 src/Org.OpenAPITools/Models/User.cs
 src/Org.OpenAPITools/OpenApi/TypeExtensions.cs
-src/Org.OpenAPITools/Org.OpenAPITools.csproj
 src/Org.OpenAPITools/Program.cs
 src/Org.OpenAPITools/Properties/launchSettings.json
 src/Org.OpenAPITools/Startup.cs
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/ApiResponse.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/ApiResponse.cs
index ef3413980eacf0261caff385d8d86a69b3d6ff12..88e45fce388b49562b5672d0bcd02ded27d25fb7 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/ApiResponse.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/ApiResponse.cs
@@ -65,7 +65,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Category.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Category.cs
index 6ac6a181baf65b83a9c4da8e71be67425dd30b64..e147a10073c92a6b25614b2e3277819cc414a718 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Category.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Category.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Order.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Order.cs
index 77a4c75a1b171ef2773e2911bac891b2d91be9f3..e9013f0ed0dfee6103b4d1741f14c7b9461ee036 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Order.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Order.cs
@@ -116,7 +116,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Pet.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Pet.cs
index a814c6e1edfeccbfe27be68240bc2b34c8d44519..d5a816cd5ee151885d81b5a5332a4f32a3e10c66 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Pet.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Pet.cs
@@ -118,7 +118,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Tag.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Tag.cs
index f0a131f617ca709c7f4011888244a43d6f5c5b64..090f95cc494f8fbe0f2c8f924d071da944ee83b0 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Tag.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/Tag.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/User.cs b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/User.cs
index 3c8a18d63cf7f5493ce8858f785a7bad26bc3574..4c6d96d08c506ce76d129740a23b9fd54d39e5a0 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/User.cs
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Models/User.cs
@@ -101,7 +101,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Org.OpenAPITools.csproj b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Org.OpenAPITools.csproj
index df1ea5462ab238dca3a8716e0bf54e5ae3fcca0c..abb035c92cbbb060d7365b683ef1bd0b63344440 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Org.OpenAPITools.csproj
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/Org.OpenAPITools.csproj
@@ -7,7 +7,7 @@
     <PreserveCompilationContext>true</PreserveCompilationContext>
     <AssemblyName>Org.OpenAPITools</AssemblyName>
     <PackageId>Org.OpenAPITools</PackageId>
-    <UserSecretsId>330f2933-9cd6-4bdd-b976-92b33eea1166</UserSecretsId>
+    <UserSecretsId>4bc22b76-ee61-45c3-aae6-47cee9badaa0</UserSecretsId>
     <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
     <DockerfileContext>..\..</DockerfileContext>
   </PropertyGroup>
diff --git a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/wwwroot/openapi-original.json b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/wwwroot/openapi-original.json
index c72a9d39daa2311a047368c1db101d568edfd382..26519713741a6cf2fe9cbefe1a78133a701ac9eb 100644
--- a/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/wwwroot/openapi-original.json
+++ b/samples/server/petstore/aspnetcore-3.0/src/Org.OpenAPITools/wwwroot/openapi-original.json
@@ -1008,5 +1008,6 @@
         "type" : "apiKey"
       }
     }
-  }
+  },
+  "x-original-swagger-version" : "2.0"
 }
diff --git a/samples/server/petstore/aspnetcore-3.1/.openapi-generator-ignore b/samples/server/petstore/aspnetcore-3.1/.openapi-generator-ignore
index 7484ee590a3894506cf063799b885428f95a71be..2832abc181293f78f1f940458904529b7eaa7ea3 100644
--- a/samples/server/petstore/aspnetcore-3.1/.openapi-generator-ignore
+++ b/samples/server/petstore/aspnetcore-3.1/.openapi-generator-ignore
@@ -21,3 +21,4 @@
 #docs/*.md
 # Then explicitly reverse the ignore rule for a single file:
 #!docs/README.md
+src/Org.OpenAPITools/Org.OpenAPITools.csproj
diff --git a/samples/server/petstore/aspnetcore-3.1/.openapi-generator/FILES b/samples/server/petstore/aspnetcore-3.1/.openapi-generator/FILES
index 4de0e6417904d60e1babca0314a21976b4db0392..f39431847dff16308121e7bc84dfc8d59cdbd1ed 100644
--- a/samples/server/petstore/aspnetcore-3.1/.openapi-generator/FILES
+++ b/samples/server/petstore/aspnetcore-3.1/.openapi-generator/FILES
@@ -19,7 +19,6 @@ src/Org.OpenAPITools/Models/Pet.cs
 src/Org.OpenAPITools/Models/Tag.cs
 src/Org.OpenAPITools/Models/User.cs
 src/Org.OpenAPITools/OpenApi/TypeExtensions.cs
-src/Org.OpenAPITools/Org.OpenAPITools.csproj
 src/Org.OpenAPITools/Program.cs
 src/Org.OpenAPITools/Properties/launchSettings.json
 src/Org.OpenAPITools/Startup.cs
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/ApiResponse.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/ApiResponse.cs
index ef3413980eacf0261caff385d8d86a69b3d6ff12..88e45fce388b49562b5672d0bcd02ded27d25fb7 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/ApiResponse.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/ApiResponse.cs
@@ -65,7 +65,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Category.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Category.cs
index 6ac6a181baf65b83a9c4da8e71be67425dd30b64..e147a10073c92a6b25614b2e3277819cc414a718 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Category.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Category.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Order.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Order.cs
index 77a4c75a1b171ef2773e2911bac891b2d91be9f3..e9013f0ed0dfee6103b4d1741f14c7b9461ee036 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Order.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Order.cs
@@ -116,7 +116,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Pet.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Pet.cs
index a814c6e1edfeccbfe27be68240bc2b34c8d44519..d5a816cd5ee151885d81b5a5332a4f32a3e10c66 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Pet.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Pet.cs
@@ -118,7 +118,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Tag.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Tag.cs
index f0a131f617ca709c7f4011888244a43d6f5c5b64..090f95cc494f8fbe0f2c8f924d071da944ee83b0 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Tag.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/Tag.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/User.cs b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/User.cs
index 3c8a18d63cf7f5493ce8858f785a7bad26bc3574..4c6d96d08c506ce76d129740a23b9fd54d39e5a0 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/User.cs
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Models/User.cs
@@ -101,7 +101,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Org.OpenAPITools.csproj b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Org.OpenAPITools.csproj
index 7b03995abb0f75533fb9decc23c3155a25d38128..7668438e876aeb33e8bc720095e372a2ecca6139 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Org.OpenAPITools.csproj
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/Org.OpenAPITools.csproj
@@ -7,7 +7,7 @@
     <PreserveCompilationContext>true</PreserveCompilationContext>
     <AssemblyName>Org.OpenAPITools</AssemblyName>
     <PackageId>Org.OpenAPITools</PackageId>
-    <UserSecretsId>0f711e23-5ed8-438c-ac28-a6dd0b863c05</UserSecretsId>
+    <UserSecretsId>4ddd97dd-77ed-459e-8cd0-dcb2f9e59a70</UserSecretsId>
     <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
     <DockerfileContext>..\..</DockerfileContext>
   </PropertyGroup>
diff --git a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/wwwroot/openapi-original.json b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/wwwroot/openapi-original.json
index c72a9d39daa2311a047368c1db101d568edfd382..26519713741a6cf2fe9cbefe1a78133a701ac9eb 100644
--- a/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/wwwroot/openapi-original.json
+++ b/samples/server/petstore/aspnetcore-3.1/src/Org.OpenAPITools/wwwroot/openapi-original.json
@@ -1008,5 +1008,6 @@
         "type" : "apiKey"
       }
     }
-  }
+  },
+  "x-original-swagger-version" : "2.0"
 }
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/ApiResponse.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/ApiResponse.cs
index ef3413980eacf0261caff385d8d86a69b3d6ff12..88e45fce388b49562b5672d0bcd02ded27d25fb7 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/ApiResponse.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/ApiResponse.cs
@@ -65,7 +65,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Category.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Category.cs
index 6ac6a181baf65b83a9c4da8e71be67425dd30b64..e147a10073c92a6b25614b2e3277819cc414a718 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Category.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Category.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Order.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Order.cs
index 77a4c75a1b171ef2773e2911bac891b2d91be9f3..e9013f0ed0dfee6103b4d1741f14c7b9461ee036 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Order.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Order.cs
@@ -116,7 +116,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Pet.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Pet.cs
index a814c6e1edfeccbfe27be68240bc2b34c8d44519..d5a816cd5ee151885d81b5a5332a4f32a3e10c66 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Pet.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Pet.cs
@@ -118,7 +118,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Tag.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Tag.cs
index f0a131f617ca709c7f4011888244a43d6f5c5b64..090f95cc494f8fbe0f2c8f924d071da944ee83b0 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Tag.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/Tag.cs
@@ -58,7 +58,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/User.cs b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/User.cs
index 3c8a18d63cf7f5493ce8858f785a7bad26bc3574..4c6d96d08c506ce76d129740a23b9fd54d39e5a0 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/User.cs
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/Models/User.cs
@@ -101,7 +101,7 @@ namespace Org.OpenAPITools.Models
         /// <returns>JSON string presentation of the object</returns>
         public string ToJson()
         {
-            return JsonConvert.SerializeObject(this, Formatting.Indented);
+            return Newtonsoft.Json.JsonConvert.SerializeObject(this, Newtonsoft.Json.Formatting.Indented);
         }
 
         /// <summary>
diff --git a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/wwwroot/openapi-original.json b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/wwwroot/openapi-original.json
index c72a9d39daa2311a047368c1db101d568edfd382..26519713741a6cf2fe9cbefe1a78133a701ac9eb 100644
--- a/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/wwwroot/openapi-original.json
+++ b/samples/server/petstore/aspnetcore/src/Org.OpenAPITools/wwwroot/openapi-original.json
@@ -1008,5 +1008,6 @@
         "type" : "apiKey"
       }
     }
-  }
+  },
+  "x-original-swagger-version" : "2.0"
 }