diff --git a/docs/generators/aspnetcore.md b/docs/generators/aspnetcore.md
index c4dc4acb6d5959a0212b9bf51ff743f188808533..f8a95fbb59717041a508efb428972526060040e8 100644
--- a/docs/generators/aspnetcore.md
+++ b/docs/generators/aspnetcore.md
@@ -41,7 +41,6 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |packageName|C# package name (convention: Title.Case).| |Org.OpenAPITools|
 |packageTitle|Specifies an AssemblyTitle for the .NET Framework global assembly attributes stored in the AssemblyInfo file.| |OpenAPI Library|
 |packageVersion|C# package version.| |1.0.0|
-|pocoModels|Build POCO Models| |false|
 |returnICollection|Return ICollection<T> instead of the concrete type.| |false|
 |sortParamsByRequiredFlag|Sort method arguments to place required parameters before optional parameters.| |true|
 |sourceFolder|source folder for generated code| |src|
diff --git a/docs/generators/perl.md b/docs/generators/perl.md
index 090ccadf1427f9384488208302749a30646358f9..34b9e1354a2ec208f11a243afc5a0737a87f3c36 100644
--- a/docs/generators/perl.md
+++ b/docs/generators/perl.md
@@ -41,8 +41,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 
 <ul class="column-ul">
 <li>ARRAY</li>
-<li>DATE</li>
-<li>DATE_TIME</li>
+<li>DateTime</li>
 <li>HASH</li>
 <li>boolean</li>
 <li>double</li>
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
index 2556ed2edf3eb74140a997f0503c219c24d00bfb..9556498b2526886738cb11634db56f672f3b0400 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
@@ -129,6 +129,9 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     protected AnnotationLibrary annotationLibrary;
     protected boolean implicitHeaders = false;
     protected String implicitHeadersRegex = null;
+    
+    // A cache to efficiently lookup schema `toModelName()` based on the schema Key
+    private Map<String, String> schemaKeyToModelNameCache = new HashMap<>();
 
     public AbstractJavaCodegen() {
         super();
@@ -829,6 +832,12 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         if (schemaMapping.containsKey(name)) {
             return schemaMapping.get(name);
         }
+        
+        // memoization
+        String origName = name;
+        if (schemaKeyToModelNameCache.containsKey(origName)) {
+            return schemaKeyToModelNameCache.get(origName);
+        }
 
         final String sanitizedName = sanitizeName(name);
 
@@ -846,6 +855,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         // camelize the model name
         // phone_number => PhoneNumber
         final String camelizedName = camelize(nameWithPrefixSuffix);
+        schemaKeyToModelNameCache.put(origName, camelizedName);
 
         // model name cannot use reserved keyword, e.g. return
         if (isReservedWord(camelizedName)) {
diff --git a/samples/client/petstore/R/.openapi-generator/FILES b/samples/client/petstore/R/.openapi-generator/FILES
index 7a05f5fdda5dbbde42ae3565c4036e12210a069c..3046316ea30be2d290a204e4119b9b5c4cf6366b 100644
--- a/samples/client/petstore/R/.openapi-generator/FILES
+++ b/samples/client/petstore/R/.openapi-generator/FILES
@@ -1,7 +1,5 @@
 .Rbuildignore
-.github/workflows/r-client.yaml
 .gitignore
-.lintr
 .travis.yml
 DESCRIPTION
 NAMESPACE
diff --git a/samples/client/petstore/R/R/animal.R b/samples/client/petstore/R/R/animal.R
index bd8d7deba7b5efce71bcf4fd44d3f9d4acd6ef9d..ad9daf1c61f00d30875ef8a35af7553e6cda2b59 100644
--- a/samples/client/petstore/R/R/animal.R
+++ b/samples/client/petstore/R/R/animal.R
@@ -26,11 +26,11 @@ Animal <- R6::R6Class(
     #' Initialize a new Animal class.
     #'
     #' @param className className
-    #' @param color color. Default to "red".
+    #' @param color color. Default to 'red'.
     #' @param ... Other optional arguments.
     #' @export
     initialize = function(
-        `className`, `color` = "red", ...
+        `className`, `color` = 'red', ...
     ) {
       if (!missing(`className`)) {
         stopifnot(is.character(`className`), length(`className`) == 1)
diff --git a/samples/client/petstore/R/R/cat.R b/samples/client/petstore/R/R/cat.R
index 42772a1cac61384e9cbaf8338dba33009d2a4222..aa353182f78362924c8dd05ef46c83e2abeef8b2 100644
--- a/samples/client/petstore/R/R/cat.R
+++ b/samples/client/petstore/R/R/cat.R
@@ -29,12 +29,12 @@ Cat <- R6::R6Class(
     #' Initialize a new Cat class.
     #'
     #' @param className className
-    #' @param color color. Default to "red".
+    #' @param color color. Default to 'red'.
     #' @param declawed declawed
     #' @param ... Other optional arguments.
     #' @export
     initialize = function(
-        `className`, `color` = "red", `declawed` = NULL, ...
+        `className`, `color` = 'red', `declawed` = NULL, ...
     ) {
       if (!missing(`className`)) {
         stopifnot(is.character(`className`), length(`className`) == 1)
diff --git a/samples/client/petstore/R/R/dog.R b/samples/client/petstore/R/R/dog.R
index dea850f7659362708ced6abfef8aae6808cc483d..d2f5a1959c480c096ec5a4c64523ebea51746a14 100644
--- a/samples/client/petstore/R/R/dog.R
+++ b/samples/client/petstore/R/R/dog.R
@@ -29,12 +29,12 @@ Dog <- R6::R6Class(
     #' Initialize a new Dog class.
     #'
     #' @param className className
-    #' @param color color. Default to "red".
+    #' @param color color. Default to 'red'.
     #' @param breed breed
     #' @param ... Other optional arguments.
     #' @export
     initialize = function(
-        `className`, `color` = "red", `breed` = NULL, ...
+        `className`, `color` = 'red', `breed` = NULL, ...
     ) {
       if (!missing(`className`)) {
         stopifnot(is.character(`className`), length(`className`) == 1)
diff --git a/samples/client/petstore/R/R/fake_api.R b/samples/client/petstore/R/R/fake_api.R
index d48ae15c566f00253b2b8b355966e2f359539939..a6c705051d345630b8caf7be17e61c20666943fd 100644
--- a/samples/client/petstore/R/R/fake_api.R
+++ b/samples/client/petstore/R/R/fake_api.R
@@ -41,8 +41,8 @@
 #' ####################  FakeDataFile  ####################
 #'
 #' library(petstore)
-#' var.dummy <- "dummy_example" # character | dummy required parameter
-#' var.var_data_file <- "var_data_file_example" # character | header data file
+#' var.dummy <- 'dummy_example' # character | dummy required parameter
+#' var.var_data_file <- 'var_data_file_example' # character | header data file
 #'
 #' #test data_file to ensure it's escaped correctly
 #' api.instance <- FakeApi$new()
diff --git a/samples/client/petstore/R/R/pet_api.R b/samples/client/petstore/R/R/pet_api.R
index 37a27ce94084f48c938da0ccd333141d21fa0bcd..edb3e18579cbf8a7ea5a29e0828db1471a7d2107 100644
--- a/samples/client/petstore/R/R/pet_api.R
+++ b/samples/client/petstore/R/R/pet_api.R
@@ -286,7 +286,7 @@
 #'
 #' library(petstore)
 #' var.pet_id <- 56 # integer | Pet id to delete
-#' var.api_key <- "api_key_example" # character | 
+#' var.api_key <- 'api_key_example' # character | 
 #'
 #' #Deletes a pet
 #' api.instance <- PetApi$new()
@@ -312,7 +312,7 @@
 #' ####################  FindPetsByStatus  ####################
 #'
 #' library(petstore)
-#' var.status <- ["status_example"] # array[character] | Status values that need to be considered for filter
+#' var.status <- ['status_example'] # array[character] | Status values that need to be considered for filter
 #'
 #' #Finds Pets by status
 #' api.instance <- PetApi$new()
@@ -340,7 +340,7 @@
 #' ####################  FindPetsByTags  ####################
 #'
 #' library(petstore)
-#' var.tags <- ["tags_example"] # array[character] | Tags to filter by
+#' var.tags <- ['tags_example'] # array[character] | Tags to filter by
 #'
 #' #Finds Pets by tags
 #' api.instance <- PetApi$new()
@@ -453,8 +453,8 @@
 #'
 #' library(petstore)
 #' var.pet_id <- 56 # integer | ID of pet that needs to be updated
-#' var.name <- "name_example" # character | Updated name of the pet
-#' var.status <- "status_example" # character | Updated status of the pet
+#' var.name <- 'name_example' # character | Updated name of the pet
+#' var.status <- 'status_example' # character | Updated status of the pet
 #'
 #' #Updates a pet in the store with form data
 #' api.instance <- PetApi$new()
@@ -481,7 +481,7 @@
 #'
 #' library(petstore)
 #' var.pet_id <- 56 # integer | ID of pet to update
-#' var.additional_metadata <- "additional_metadata_example" # character | Additional data to pass to server
+#' var.additional_metadata <- 'additional_metadata_example' # character | Additional data to pass to server
 #' var.file <- File.new('/path/to/file') # data.frame | file to upload
 #'
 #' #uploads an image
diff --git a/samples/client/petstore/R/R/store_api.R b/samples/client/petstore/R/R/store_api.R
index 584646fc43158b37d67cec6284a0b446dd4f453a..9dea7619bc6aecdca76f2ad2cc117889d2784f24 100644
--- a/samples/client/petstore/R/R/store_api.R
+++ b/samples/client/petstore/R/R/store_api.R
@@ -119,7 +119,7 @@
 #' ####################  DeleteOrder  ####################
 #'
 #' library(petstore)
-#' var.order_id <- "order_id_example" # character | ID of the order that needs to be deleted
+#' var.order_id <- 'order_id_example' # character | ID of the order that needs to be deleted
 #'
 #' #Delete purchase order by ID
 #' api.instance <- StoreApi$new()
diff --git a/samples/client/petstore/R/R/user_api.R b/samples/client/petstore/R/R/user_api.R
index 10dead6d87c9681ac0d00ec01637445f427a37e0..de6ab7011a43aa11b0071c4e12569e4e86763400 100644
--- a/samples/client/petstore/R/R/user_api.R
+++ b/samples/client/petstore/R/R/user_api.R
@@ -276,7 +276,7 @@
 #' ####################  DeleteUser  ####################
 #'
 #' library(petstore)
-#' var.username <- "username_example" # character | The name that needs to be deleted
+#' var.username <- 'username_example' # character | The name that needs to be deleted
 #'
 #' #Delete user
 #' api.instance <- UserApi$new()
@@ -302,7 +302,7 @@
 #' ####################  GetUserByName  ####################
 #'
 #' library(petstore)
-#' var.username <- "username_example" # character | The name that needs to be fetched. Use user1 for testing.
+#' var.username <- 'username_example' # character | The name that needs to be fetched. Use user1 for testing.
 #'
 #' #Get user by user name
 #' api.instance <- UserApi$new()
@@ -327,8 +327,8 @@
 #' ####################  LoginUser  ####################
 #'
 #' library(petstore)
-#' var.username <- "username_example" # character | The user name for login
-#' var.password <- "password_example" # character | The password for login in clear text
+#' var.username <- 'username_example' # character | The user name for login
+#' var.password <- 'password_example' # character | The password for login in clear text
 #'
 #' #Logs user into the system
 #' api.instance <- UserApi$new()
@@ -378,7 +378,7 @@
 #' ####################  UpdateUser  ####################
 #'
 #' library(petstore)
-#' var.username <- "username_example" # character | name that need to be deleted
+#' var.username <- 'username_example' # character | name that need to be deleted
 #' var.user <- User$new() # User | Updated user object
 #'
 #' #Updated user
diff --git a/samples/client/petstore/R/docs/Animal.md b/samples/client/petstore/R/docs/Animal.md
index 5cb0eb8bbf27b83fb5480f2f8f7a0c79b37db836..f21cc2147b6b457f9c8658974c28c5fa8a437ed3 100644
--- a/samples/client/petstore/R/docs/Animal.md
+++ b/samples/client/petstore/R/docs/Animal.md
@@ -5,6 +5,6 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **className** | **character** |  | 
-**color** | **character** |  | [optional] [default to &quot;red&quot;]
+**color** | **character** |  | [optional] [default to &#39;red&#39;]
 
 
diff --git a/samples/client/petstore/R/docs/Cat.md b/samples/client/petstore/R/docs/Cat.md
index ba23ea86a33efe7849a96082c6e1446725493287..d6e99c85c69df79948b8ed76a673abc0fc239749 100644
--- a/samples/client/petstore/R/docs/Cat.md
+++ b/samples/client/petstore/R/docs/Cat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **className** | **character** |  | 
-**color** | **character** |  | [optional] [default to &quot;red&quot;]
+**color** | **character** |  | [optional] [default to &#39;red&#39;]
 **declawed** | **character** |  | [optional] 
 
 
diff --git a/samples/client/petstore/R/docs/Dog.md b/samples/client/petstore/R/docs/Dog.md
index b2e732df451b9e92459a7e3a21c6c5a431593098..6a7c1f53a14a98416a98cf12f185e3252a4eb799 100644
--- a/samples/client/petstore/R/docs/Dog.md
+++ b/samples/client/petstore/R/docs/Dog.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **className** | **character** |  | 
-**color** | **character** |  | [optional] [default to &quot;red&quot;]
+**color** | **character** |  | [optional] [default to &#39;red&#39;]
 **breed** | **character** |  | [optional] 
 
 
diff --git a/samples/client/petstore/R/docs/FakeApi.md b/samples/client/petstore/R/docs/FakeApi.md
index 484ca98a1d6262d267206098779645349d7472c7..55132bdfcf70af28da2c755dbd7a6d45c2e2a715 100644
--- a/samples/client/petstore/R/docs/FakeApi.md
+++ b/samples/client/petstore/R/docs/FakeApi.md
@@ -18,8 +18,8 @@ test data_file to ensure it's escaped correctly
 ```R
 library(petstore)
 
-var_dummy <- "dummy_example" # character | dummy required parameter
-var_var_data_file <- "var_data_file_example" # character | header data file
+var_dummy <- 'dummy_example' # character | dummy required parameter
+var_var_data_file <- 'var_data_file_example' # character | header data file
 
 #test data_file to ensure it's escaped correctly
 api_instance <- FakeApi$new()
diff --git a/samples/client/petstore/R/docs/PetApi.md b/samples/client/petstore/R/docs/PetApi.md
index a89cf8fac8f391f66b1dfd211e47a4f4ce71fa52..7211545a44b74cda9c4c2788eefa2d58ac728c24 100644
--- a/samples/client/petstore/R/docs/PetApi.md
+++ b/samples/client/petstore/R/docs/PetApi.md
@@ -88,7 +88,7 @@ Deletes a pet
 library(petstore)
 
 var_pet_id <- 56 # integer | Pet id to delete
-var_api_key <- "api_key_example" # character | 
+var_api_key <- 'api_key_example' # character | 
 
 #Deletes a pet
 api_instance <- PetApi$new()
@@ -457,8 +457,8 @@ Updates a pet in the store with form data
 library(petstore)
 
 var_pet_id <- 56 # integer | ID of pet that needs to be updated
-var_name <- "name_example" # character | Updated name of the pet
-var_status <- "status_example" # character | Updated status of the pet
+var_name <- 'name_example' # character | Updated name of the pet
+var_status <- 'status_example' # character | Updated status of the pet
 
 #Updates a pet in the store with form data
 api_instance <- PetApi$new()
@@ -517,7 +517,7 @@ uploads an image
 library(petstore)
 
 var_pet_id <- 56 # integer | ID of pet to update
-var_additional_metadata <- "additional_metadata_example" # character | Additional data to pass to server
+var_additional_metadata <- 'additional_metadata_example' # character | Additional data to pass to server
 var_file <- File.new('/path/to/file') # data.frame | file to upload
 
 #uploads an image
diff --git a/samples/client/petstore/R/docs/StoreApi.md b/samples/client/petstore/R/docs/StoreApi.md
index 31343a84ea0125efea0c11a53e8f4c7b27dbfe65..2caef65f3d29f8625a382d1310ea13c43a66b243 100644
--- a/samples/client/petstore/R/docs/StoreApi.md
+++ b/samples/client/petstore/R/docs/StoreApi.md
@@ -21,7 +21,7 @@ For valid response try integer IDs with value < 1000. Anything above 1000 or non
 ```R
 library(petstore)
 
-var_order_id <- "order_id_example" # character | ID of the order that needs to be deleted
+var_order_id <- 'order_id_example' # character | ID of the order that needs to be deleted
 
 #Delete purchase order by ID
 api_instance <- StoreApi$new()
diff --git a/samples/client/petstore/R/docs/UserApi.md b/samples/client/petstore/R/docs/UserApi.md
index 3382f734cef2b3e669a609aa7c4e9a37cc592f26..d292094b7e8fe063331b1e2bc95011ce1fef7a67 100644
--- a/samples/client/petstore/R/docs/UserApi.md
+++ b/samples/client/petstore/R/docs/UserApi.md
@@ -193,7 +193,7 @@ This can only be done by the logged in user.
 ```R
 library(petstore)
 
-var_username <- "username_example" # character | The name that needs to be deleted
+var_username <- 'username_example' # character | The name that needs to be deleted
 
 #Delete user
 api_instance <- UserApi$new()
@@ -250,7 +250,7 @@ Get user by user name
 ```R
 library(petstore)
 
-var_username <- "username_example" # character | The name that needs to be fetched. Use user1 for testing.
+var_username <- 'username_example' # character | The name that needs to be fetched. Use user1 for testing.
 
 #Get user by user name
 api_instance <- UserApi$new()
@@ -310,8 +310,8 @@ Logs user into the system
 ```R
 library(petstore)
 
-var_username <- "username_example" # character | The user name for login
-var_password <- "password_example" # character | The password for login in clear text
+var_username <- 'username_example' # character | The user name for login
+var_password <- 'password_example' # character | The password for login in clear text
 
 #Logs user into the system
 api_instance <- UserApi$new()
@@ -423,7 +423,7 @@ This can only be done by the logged in user.
 ```R
 library(petstore)
 
-var_username <- "username_example" # character | name that need to be deleted
+var_username <- 'username_example' # character | name that need to be deleted
 var_user <- User$new(123, "username_example", "firstName_example", "lastName_example", "email_example", "password_example", "phone_example", 123) # User | Updated user object
 
 #Updated user
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/ChildCat.cs
index e5f952880eb274685be5c5af43c46817dc4224bc..6358e859ce1745fbbf71bdf3ce479a74c07a96c9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-ConditionalSerialization/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -53,8 +53,8 @@ namespace Org.OpenAPITools.Model
         /// Gets or Sets PetType
         /// </summary>
 
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType
         {
             get{ return _PetType;}
             set
@@ -63,7 +63,7 @@ namespace Org.OpenAPITools.Model
                 _flagPetType = true;
             }
         }
-        private PetTypeEnum? _PetType;
+        private PetTypeEnum _PetType;
         private bool _flagPetType;
 
         /// <summary>
@@ -86,9 +86,10 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
+            this._PetType = petType;
             this._Name = name;
             if (this.Name != null)
             {
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/ChildCat.cs
index 2420d1295542d655292a4c007b397a19529811ec..a6603b7cb85824f3b38deeb4811c84ef050df016 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-httpclient/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -53,8 +53,8 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Gets or Sets PetType
         /// </summary>
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType { get; set; }
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType { get; set; }
         /// <summary>
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
@@ -67,11 +67,11 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
-            this.Name = name;
             this.PetType = petType;
+            this.Name = name;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/ChildCat.cs
index 4c60ed776cdac3e392f5d2eea31890a3bd0dd65e..7a15a5297df2b604f05d96541c3ce8f8ba3a5ecb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net47/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -52,8 +52,8 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Gets or Sets PetType
         /// </summary>
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType { get; set; }
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType { get; set; }
         /// <summary>
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
@@ -66,11 +66,11 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
-            this.Name = name;
             this.PetType = petType;
+            this.Name = name;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/ChildCat.cs
index 4c60ed776cdac3e392f5d2eea31890a3bd0dd65e..7a15a5297df2b604f05d96541c3ce8f8ba3a5ecb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient-net5.0/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -52,8 +52,8 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Gets or Sets PetType
         /// </summary>
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType { get; set; }
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType { get; set; }
         /// <summary>
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
@@ -66,11 +66,11 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
-            this.Name = name;
             this.PetType = petType;
+            this.Name = name;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ChildCat.cs
index 4c60ed776cdac3e392f5d2eea31890a3bd0dd65e..7a15a5297df2b604f05d96541c3ce8f8ba3a5ecb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -52,8 +52,8 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Gets or Sets PetType
         /// </summary>
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType { get; set; }
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType { get; set; }
         /// <summary>
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
@@ -66,11 +66,11 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
-            this.Name = name;
             this.PetType = petType;
+            this.Name = name;
             this.AdditionalProperties = new Dictionary<string, object>();
         }
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/ChildCat.md b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/ChildCat.md
index 072ad05b36d234558f9941277e7a69fe44263eb6..8ce6449e5f2247bd36e04d3003e127397180ca3c 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/ChildCat.md
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/docs/ChildCat.md
@@ -5,7 +5,7 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **Name** | **string** |  | [optional] 
-**PetType** | **string** |  | [optional] [default to PetTypeEnum.ChildCat]
+**PetType** | **string** |  | [default to PetTypeEnum.ChildCat]
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ChildCat.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ChildCat.cs
index c6c7222d7a653088fe963d7bccc6b51a76b2bf3b..d2b819278854b3af080919b1f4c3813cc00a5ce2 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ChildCat.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ChildCat.cs
@@ -52,8 +52,8 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         /// Gets or Sets PetType
         /// </summary>
-        [DataMember(Name = "pet_type", EmitDefaultValue = false)]
-        public PetTypeEnum? PetType { get; set; }
+        [DataMember(Name = "pet_type", IsRequired = true, EmitDefaultValue = false)]
+        public PetTypeEnum PetType { get; set; }
         /// <summary>
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
@@ -63,11 +63,11 @@ namespace Org.OpenAPITools.Model
         /// Initializes a new instance of the <see cref="ChildCat" /> class.
         /// </summary>
         /// <param name="name">name.</param>
-        /// <param name="petType">petType (default to PetTypeEnum.ChildCat).</param>
-        public ChildCat(string name = default(string), PetTypeEnum? petType = PetTypeEnum.ChildCat) : base()
+        /// <param name="petType">petType (required) (default to PetTypeEnum.ChildCat).</param>
+        public ChildCat(string name = default(string), PetTypeEnum petType = PetTypeEnum.ChildCat) : base()
         {
-            this.Name = name;
             this.PetType = petType;
+            this.Name = name;
         }
 
         /// <summary>
diff --git a/samples/client/petstore/java/jersey3/docs/ChildCat.md b/samples/client/petstore/java/jersey3/docs/ChildCat.md
index 3f39832529b9475c23d3830e1332f683aa79a154..6a114cc4ffb3b5c0c2c84ffdd4a11bba88369b27 100644
--- a/samples/client/petstore/java/jersey3/docs/ChildCat.md
+++ b/samples/client/petstore/java/jersey3/docs/ChildCat.md
@@ -8,7 +8,7 @@
 | Name | Type | Description | Notes |
 |------------ | ------------- | ------------- | -------------|
 |**name** | **String** |  |  [optional] |
-|**petType** | [**String**](#String) |  |  [optional] |
+|**petType** | [**String**](#String) |  |  |
 
 
 
diff --git a/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/ChildCat.java b/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/ChildCat.java
index e0ce86c3f9143c0cc56fcf7c98bf6fdd628a5cca..8e16e6fedd225d769e8b698c8fc36b584296103d 100644
--- a/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/ChildCat.java
+++ b/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/ChildCat.java
@@ -105,10 +105,10 @@ public class ChildCat extends ParentPet {
    * Get petType
    * @return petType
   **/
-  @jakarta.annotation.Nullable
-  @ApiModelProperty(value = "")
+  @jakarta.annotation.Nonnull
+  @ApiModelProperty(required = true, value = "")
   @JsonProperty(JSON_PROPERTY_PET_TYPE)
-  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
 
   public String getPetType() {
     return petType;
@@ -116,7 +116,7 @@ public class ChildCat extends ParentPet {
 
 
   @JsonProperty(JSON_PROPERTY_PET_TYPE)
-  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
   public void setPetType(String petType) {
     if (!PET_TYPE_VALUES.contains(petType)) {
       throw new IllegalArgumentException(petType + " is invalid. Possible values for petType: " + String.join(", ", PET_TYPE_VALUES));
diff --git a/samples/client/petstore/perl/docs/FakeApi.md b/samples/client/petstore/perl/docs/FakeApi.md
index e028d69b6c3abe7f62a55839751a8a99d8ac92c3..fbd1c1d042f9c9c69df985b564c05221c7b9cfe7 100644
--- a/samples/client/petstore/perl/docs/FakeApi.md
+++ b/samples/client/petstore/perl/docs/FakeApi.md
@@ -558,8 +558,8 @@ my $int64 = 789; # int | None
 my $float = 3.4; # double | None
 my $string = "string_example"; # string | None
 my $binary = "/path/to/file"; # string | None
-my $date = DateTime->from_epoch(epoch => str2time('null')); # DATE | None
-my $date_time = DateTime->from_epoch(epoch => str2time('null')); # DATE_TIME | None
+my $date = DateTime->from_epoch(epoch => str2time('null')); # DateTime | None
+my $date_time = DateTime->from_epoch(epoch => str2time('null')); # DateTime | None
 my $password = "password_example"; # string | None
 my $callback = "callback_example"; # string | None
 
@@ -585,8 +585,8 @@ Name | Type | Description  | Notes
  **float** | **double**| None | [optional] 
  **string** | **string**| None | [optional] 
  **binary** | **string****string**| None | [optional] 
- **date** | **DATE**| None | [optional] 
- **date_time** | **DATE_TIME**| None | [optional] 
+ **date** | **DateTime**| None | [optional] 
+ **date_time** | **DateTime**| None | [optional] 
  **password** | **string**| None | [optional] 
  **callback** | **string**| None | [optional] 
 
diff --git a/samples/client/petstore/perl/docs/FormatTest.md b/samples/client/petstore/perl/docs/FormatTest.md
index bd9dd2565c24a1af4252978817f0e6bbbd2f5ce4..886a93b4fed492645d42b0a62df3252cc51ab312 100644
--- a/samples/client/petstore/perl/docs/FormatTest.md
+++ b/samples/client/petstore/perl/docs/FormatTest.md
@@ -14,12 +14,12 @@ Name | Type | Description | Notes
 **number** | **double** |  | 
 **float** | **double** |  | [optional] 
 **double** | **double** |  | [optional] 
-**decimal** | **double** |  | [optional] 
+**decimal** | [**Decimal**](Decimal.md) |  | [optional] 
 **string** | **string** |  | [optional] 
 **byte** | **string** |  | 
 **binary** | **string** |  | [optional] 
-**date** | **DATE** |  | 
-**date_time** | **DATE_TIME** |  | [optional] 
+**date** | **DateTime** |  | 
+**date_time** | **DateTime** |  | [optional] 
 **uuid** | **string** |  | [optional] 
 **password** | **string** |  | 
 **pattern_with_digits** | **string** | A string that is a 10 digit number. Can have leading zeros. | [optional] 
diff --git a/samples/client/petstore/perl/docs/MixedPropertiesAndAdditionalPropertiesClass.md b/samples/client/petstore/perl/docs/MixedPropertiesAndAdditionalPropertiesClass.md
index 9fe5279da09ca07400e266456ed619553ab77da7..f2720cf57b5b184fe20467339953a6ce669362bd 100644
--- a/samples/client/petstore/perl/docs/MixedPropertiesAndAdditionalPropertiesClass.md
+++ b/samples/client/petstore/perl/docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -9,7 +9,7 @@ use WWW::OpenAPIClient::Object::MixedPropertiesAndAdditionalPropertiesClass;
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **uuid** | **string** |  | [optional] 
-**date_time** | **DATE_TIME** |  | [optional] 
+**date_time** | **DateTime** |  | [optional] 
 **map** | [**HASH[string,Animal]**](Animal.md) |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
diff --git a/samples/client/petstore/perl/docs/NullableClass.md b/samples/client/petstore/perl/docs/NullableClass.md
index 200aaa3d783524361a79f0a1506b057c03f4a46f..326c42317cb8ed857d1ccdfe7da66095cabf8551 100644
--- a/samples/client/petstore/perl/docs/NullableClass.md
+++ b/samples/client/petstore/perl/docs/NullableClass.md
@@ -12,8 +12,8 @@ Name | Type | Description | Notes
 **number_prop** | **double** |  | [optional] 
 **boolean_prop** | **boolean** |  | [optional] 
 **string_prop** | **string** |  | [optional] 
-**date_prop** | **DATE** |  | [optional] 
-**datetime_prop** | **DATE_TIME** |  | [optional] 
+**date_prop** | **DateTime** |  | [optional] 
+**datetime_prop** | **DateTime** |  | [optional] 
 **array_nullable_prop** | **ARRAY[object]** |  | [optional] 
 **array_and_items_nullable_prop** | **ARRAY[object]** |  | [optional] 
 **array_items_nullable** | **ARRAY[object]** |  | [optional] 
diff --git a/samples/client/petstore/perl/docs/Order.md b/samples/client/petstore/perl/docs/Order.md
index 2b33f1d4d7f615aed97ebc27429e0c2e30b571eb..356ad67f45d76e92cf6ead378b24c50a908f307a 100644
--- a/samples/client/petstore/perl/docs/Order.md
+++ b/samples/client/petstore/perl/docs/Order.md
@@ -11,7 +11,7 @@ Name | Type | Description | Notes
 **id** | **int** |  | [optional] 
 **pet_id** | **int** |  | [optional] 
 **quantity** | **int** |  | [optional] 
-**ship_date** | **DATE_TIME** |  | [optional] 
+**ship_date** | **DateTime** |  | [optional] 
 **status** | **string** | Order Status | [optional] 
 **complete** | **boolean** |  | [optional] [default to false]
 
diff --git a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/FakeApi.pm b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/FakeApi.pm
index 2712407215f0aec8d743fb46a7e44f4b6d71ac52..9c702e1c1d65769fb758ac8e084383b563b53c6b 100644
--- a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/FakeApi.pm
+++ b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/FakeApi.pm
@@ -759,8 +759,8 @@ sub test_client_model {
 # @param double $float None (optional)
 # @param string $string None (optional)
 # @param string $binary None (optional)
-# @param DATE $date None (optional)
-# @param DATE_TIME $date_time None (optional)
+# @param DateTime $date None (optional)
+# @param DateTime $date_time None (optional)
 # @param string $password None (optional)
 # @param string $callback None (optional)
 {
@@ -816,12 +816,12 @@ sub test_client_model {
         required => '0',
     },
     'date' => {
-        data_type => 'DATE',
+        data_type => 'DateTime',
         description => 'None',
         required => '0',
     },
     'date_time' => {
-        data_type => 'DATE_TIME',
+        data_type => 'DateTime',
         description => 'None',
         required => '0',
     },
diff --git a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/FormatTest.pm b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/FormatTest.pm
index d0ad7e619ff513dbf330070e023871051c5904dd..dd65f853a924801b0d74cf11c9624d64c503a101 100644
--- a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/FormatTest.pm
+++ b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/FormatTest.pm
@@ -30,6 +30,7 @@ use Log::Any qw($log);
 use Date::Parse;
 use DateTime;
 
+use WWW::OpenAPIClient::Object::Decimal;
 
 use base ("Class::Accessor", "Class::Data::Inheritable");
 
@@ -256,7 +257,7 @@ __PACKAGE__->method_documentation({
         read_only => '',
             },
     'decimal' => {
-        datatype => 'double',
+        datatype => 'Decimal',
         base_name => 'decimal',
         description => '',
         format => '',
@@ -284,14 +285,14 @@ __PACKAGE__->method_documentation({
         read_only => '',
             },
     'date' => {
-        datatype => 'DATE',
+        datatype => 'DateTime',
         base_name => 'date',
         description => '',
         format => '',
         read_only => '',
             },
     'date_time' => {
-        datatype => 'DATE_TIME',
+        datatype => 'DateTime',
         base_name => 'dateTime',
         description => '',
         format => '',
@@ -334,12 +335,12 @@ __PACKAGE__->openapi_types( {
     'number' => 'double',
     'float' => 'double',
     'double' => 'double',
-    'decimal' => 'double',
+    'decimal' => 'Decimal',
     'string' => 'string',
     'byte' => 'string',
     'binary' => 'string',
-    'date' => 'DATE',
-    'date_time' => 'DATE_TIME',
+    'date' => 'DateTime',
+    'date_time' => 'DateTime',
     'uuid' => 'string',
     'password' => 'string',
     'pattern_with_digits' => 'string',
diff --git a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/MixedPropertiesAndAdditionalPropertiesClass.pm b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/MixedPropertiesAndAdditionalPropertiesClass.pm
index b39798d87ecff5cf11b08eadf317c7f18a90b3cb..88be77650ec0548fef7cf85fddf38bfe5a0810ad 100644
--- a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/MixedPropertiesAndAdditionalPropertiesClass.pm
+++ b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/MixedPropertiesAndAdditionalPropertiesClass.pm
@@ -222,7 +222,7 @@ __PACKAGE__->method_documentation({
         read_only => '',
             },
     'date_time' => {
-        datatype => 'DATE_TIME',
+        datatype => 'DateTime',
         base_name => 'dateTime',
         description => '',
         format => '',
@@ -239,7 +239,7 @@ __PACKAGE__->method_documentation({
 
 __PACKAGE__->openapi_types( {
     'uuid' => 'string',
-    'date_time' => 'DATE_TIME',
+    'date_time' => 'DateTime',
     'map' => 'HASH[string,Animal]'
 } );
 
diff --git a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/NullableClass.pm b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/NullableClass.pm
index e83d3d247ea633a21c6a416455679c818a54cd53..92ece221b8d6635e9c8a182a6fdc02e4902e8829 100644
--- a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/NullableClass.pm
+++ b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/NullableClass.pm
@@ -242,14 +242,14 @@ __PACKAGE__->method_documentation({
         read_only => '',
             },
     'date_prop' => {
-        datatype => 'DATE',
+        datatype => 'DateTime',
         base_name => 'date_prop',
         description => '',
         format => '',
         read_only => '',
             },
     'datetime_prop' => {
-        datatype => 'DATE_TIME',
+        datatype => 'DateTime',
         base_name => 'datetime_prop',
         description => '',
         format => '',
@@ -304,8 +304,8 @@ __PACKAGE__->openapi_types( {
     'number_prop' => 'double',
     'boolean_prop' => 'boolean',
     'string_prop' => 'string',
-    'date_prop' => 'DATE',
-    'datetime_prop' => 'DATE_TIME',
+    'date_prop' => 'DateTime',
+    'datetime_prop' => 'DateTime',
     'array_nullable_prop' => 'ARRAY[object]',
     'array_and_items_nullable_prop' => 'ARRAY[object]',
     'array_items_nullable' => 'ARRAY[object]',
diff --git a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/Order.pm b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/Order.pm
index 546fa99bd5effd23d0005482ea7a4a70497a5244..e206f876157623c231ad24754069b0086d452dac 100644
--- a/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/Order.pm
+++ b/samples/client/petstore/perl/lib/WWW/OpenAPIClient/Object/Order.pm
@@ -235,7 +235,7 @@ __PACKAGE__->method_documentation({
         read_only => '',
             },
     'ship_date' => {
-        datatype => 'DATE_TIME',
+        datatype => 'DateTime',
         base_name => 'shipDate',
         description => '',
         format => '',
@@ -261,7 +261,7 @@ __PACKAGE__->openapi_types( {
     'id' => 'int',
     'pet_id' => 'int',
     'quantity' => 'int',
-    'ship_date' => 'DATE_TIME',
+    'ship_date' => 'DateTime',
     'status' => 'string',
     'complete' => 'boolean'
 } );
diff --git a/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts b/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
index 0d480e40bc03fe05f90b6289711aceffea266578..572cae522364d9e7ca8993e791976bf6749d602a 100644
--- a/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
+++ b/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
@@ -359,7 +359,7 @@ export interface ChildCat extends ParentPet {
      * @type {string}
      * @memberof ChildCat
      */
-    'pet_type'?: ChildCatPetTypeEnum;
+    'pet_type': ChildCatPetTypeEnum;
 }
 
 export const ChildCatPetTypeEnum = {
diff --git a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/additionalproperties_should_not_look_in_applicators.py b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/additionalproperties_should_not_look_in_applicators.py
index 5f2482fc088f042f8055f512c004945aac69ca02..11a38935e5db534d15e79fde75c300939edf2580 100644
--- a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/additionalproperties_should_not_look_in_applicators.py
+++ b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/additionalproperties_should_not_look_in_applicators.py
@@ -89,27 +89,7 @@ class AdditionalpropertiesShouldNotLookInApplicators(
         # code would be run when this module is imported, and these composed
         # classes don't exist yet because their module has not finished
         # loading
-        
-        
-        class allOf_0(
-            AnyTypeSchema
-        ):
-            foo = AnyTypeSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                foo: typing.Union[foo, Unset] = unset,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'allOf_0':
-                return super().__new__(
-                    cls,
-                    *args,
-                    foo=foo,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
+        allOf_0 = AnyTypeSchema
         return {
             'allOf': [
                 allOf_0,
diff --git a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof.py b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof.py
index 51d4cec94c31e80f75e07e34a280e39562eb0516..d6175f9fe968db7592edcdc4187a037d10fd8ebb 100644
--- a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof.py
+++ b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof.py
@@ -88,54 +88,8 @@ class Allof(
         # code would be run when this module is imported, and these composed
         # classes don't exist yet because their module has not finished
         # loading
-        
-        
-        class allOf_0(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'bar',
-            ))
-            bar = IntSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                bar: bar,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'allOf_0':
-                return super().__new__(
-                    cls,
-                    *args,
-                    bar=bar,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
-        
-        
-        class allOf_1(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'foo',
-            ))
-            foo = StrSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                foo: foo,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'allOf_1':
-                return super().__new__(
-                    cls,
-                    *args,
-                    foo=foo,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
+        allOf_0 = AnyTypeSchema
+        allOf_1 = AnyTypeSchema
         return {
             'allOf': [
                 allOf_0,
diff --git a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof_with_base_schema.py b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof_with_base_schema.py
index b0a4665f9b312f58cf719938b5b6a87920a3cea4..86b47bc86dd6c904399b939f8c11bdcad502e75d 100644
--- a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof_with_base_schema.py
+++ b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/allof_with_base_schema.py
@@ -92,54 +92,8 @@ class AllofWithBaseSchema(
         # code would be run when this module is imported, and these composed
         # classes don't exist yet because their module has not finished
         # loading
-        
-        
-        class allOf_0(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'foo',
-            ))
-            foo = StrSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                foo: foo,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'allOf_0':
-                return super().__new__(
-                    cls,
-                    *args,
-                    foo=foo,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
-        
-        
-        class allOf_1(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'baz',
-            ))
-            baz = NoneSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                baz: baz,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'allOf_1':
-                return super().__new__(
-                    cls,
-                    *args,
-                    baz=baz,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
+        allOf_0 = AnyTypeSchema
+        allOf_1 = AnyTypeSchema
         return {
             'allOf': [
                 allOf_0,
diff --git a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/anyof_complex_types.py b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/anyof_complex_types.py
index 918cb35d65c33d2e8e3ec7fbdbd2b4e935a04a7d..151ce57c3c7beee268e096046df7e2148c632e46 100644
--- a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/anyof_complex_types.py
+++ b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/anyof_complex_types.py
@@ -88,54 +88,8 @@ class AnyofComplexTypes(
         # code would be run when this module is imported, and these composed
         # classes don't exist yet because their module has not finished
         # loading
-        
-        
-        class anyOf_0(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'bar',
-            ))
-            bar = IntSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                bar: bar,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'anyOf_0':
-                return super().__new__(
-                    cls,
-                    *args,
-                    bar=bar,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
-        
-        
-        class anyOf_1(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'foo',
-            ))
-            foo = StrSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                foo: foo,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'anyOf_1':
-                return super().__new__(
-                    cls,
-                    *args,
-                    foo=foo,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
+        anyOf_0 = AnyTypeSchema
+        anyOf_1 = AnyTypeSchema
         return {
             'allOf': [
             ],
diff --git a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/oneof_complex_types.py b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/oneof_complex_types.py
index e3c9861ad4927468390f3f493d76a2da5e9a6772..162d76e60285be8ef5135aa83e18120c7468fd9c 100644
--- a/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/oneof_complex_types.py
+++ b/samples/openapi3/client/3_0_3_unit_test/python-experimental/unit_test_api/model/oneof_complex_types.py
@@ -88,54 +88,8 @@ class OneofComplexTypes(
         # code would be run when this module is imported, and these composed
         # classes don't exist yet because their module has not finished
         # loading
-        
-        
-        class oneOf_0(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'bar',
-            ))
-            bar = IntSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                bar: bar,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'oneOf_0':
-                return super().__new__(
-                    cls,
-                    *args,
-                    bar=bar,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
-        
-        
-        class oneOf_1(
-            AnyTypeSchema
-        ):
-            _required_property_names = set((
-                'foo',
-            ))
-            foo = StrSchema
-        
-            def __new__(
-                cls,
-                *args: typing.Union[dict, frozendict, str, date, datetime, int, float, decimal.Decimal, None, list, tuple, bytes],
-                foo: foo,
-                _configuration: typing.Optional[Configuration] = None,
-                **kwargs: typing.Type[Schema],
-            ) -> 'oneOf_1':
-                return super().__new__(
-                    cls,
-                    *args,
-                    foo=foo,
-                    _configuration=_configuration,
-                    **kwargs,
-                )
+        oneOf_0 = AnyTypeSchema
+        oneOf_1 = AnyTypeSchema
         return {
             'allOf': [
             ],
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/docs/ChildCat.md b/samples/openapi3/client/petstore/java/jersey2-java8/docs/ChildCat.md
index 3f39832529b9475c23d3830e1332f683aa79a154..6a114cc4ffb3b5c0c2c84ffdd4a11bba88369b27 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/docs/ChildCat.md
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/docs/ChildCat.md
@@ -8,7 +8,7 @@
 | Name | Type | Description | Notes |
 |------------ | ------------- | ------------- | -------------|
 |**name** | **String** |  |  [optional] |
-|**petType** | [**String**](#String) |  |  [optional] |
+|**petType** | [**String**](#String) |  |  |
 
 
 
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
index ae123669a7da502ce5c51dd75aa9a16302b17b12..0e2970ef036105eaa621d0c66604ebe344fb0040 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
@@ -105,10 +105,10 @@ public class ChildCat extends ParentPet {
    * Get petType
    * @return petType
   **/
-  @javax.annotation.Nullable
-  @ApiModelProperty(value = "")
+  @javax.annotation.Nonnull
+  @ApiModelProperty(required = true, value = "")
   @JsonProperty(JSON_PROPERTY_PET_TYPE)
-  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
 
   public String getPetType() {
     return petType;
@@ -116,7 +116,7 @@ public class ChildCat extends ParentPet {
 
 
   @JsonProperty(JSON_PROPERTY_PET_TYPE)
-  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
   public void setPetType(String petType) {
     if (!PET_TYPE_VALUES.contains(petType)) {
       throw new IllegalArgumentException(petType + " is invalid. Possible values for petType: " + String.join(", ", PET_TYPE_VALUES));
diff --git a/samples/openapi3/client/petstore/python-experimental/docs/PetApi.md b/samples/openapi3/client/petstore/python-experimental/docs/PetApi.md
index d8ee4cb32fc8f6cf5343cba5c738c6e8fb4ee2df..7b9ab23bc5db99d419df25457c996f4082d2dc2c 100644
--- a/samples/openapi3/client/petstore/python-experimental/docs/PetApi.md
+++ b/samples/openapi3/client/petstore/python-experimental/docs/PetApi.md
@@ -1315,7 +1315,7 @@ skip_deserialization | bool | default is False | when True, headers and body wil
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **additionalMetadata** | **str** | Additional data to pass to server | [optional] 
-**file** | **file_type** | file to upload | [optional] 
+**file** | **file_type** | file to upload | 
 **any string name** | **bool, date, datetime, dict, float, int, list, str, none_type** | any string name can be used but the value must be the correct type | [optional]
 
 ### path_params
diff --git a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/endpoint_parameters.py b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/endpoint_parameters.py
index d4bfb218fd0d059677e5e318b317495464475ec1..666b832fc7c8500663c217ad4b9f4af8e763fc27 100644
--- a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/endpoint_parameters.py
+++ b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/endpoint_parameters.py
@@ -73,10 +73,6 @@ class SchemaForRequestBodyApplicationXWwwFormUrlencoded(
     DictSchema
 ):
     _required_property_names = set((
-        'number',
-        'double',
-        'pattern_without_delimiter',
-        'byte',
     ))
     
     
@@ -175,10 +171,6 @@ class SchemaForRequestBodyApplicationXWwwFormUrlencoded(
     def __new__(
         cls,
         *args: typing.Union[dict, frozendict, ],
-        number: number,
-        double: double,
-        pattern_without_delimiter: pattern_without_delimiter,
-        byte: byte,
         integer: typing.Union[integer, Unset] = unset,
         int32: typing.Union[int32, Unset] = unset,
         int64: typing.Union[int64, Unset] = unset,
@@ -194,10 +186,6 @@ class SchemaForRequestBodyApplicationXWwwFormUrlencoded(
         return super().__new__(
             cls,
             *args,
-            number=number,
-            double=double,
-            pattern_without_delimiter=pattern_without_delimiter,
-            byte=byte,
             integer=integer,
             int32=int32,
             int64=int64,
diff --git a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/json_form_data.py b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/json_form_data.py
index ce7e5851c6afd99e675274e492eeff1c89b4e43b..34dfe5627cecc4b79b76518820420b4a27ea2fc8 100644
--- a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/json_form_data.py
+++ b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/json_form_data.py
@@ -73,8 +73,6 @@ class SchemaForRequestBodyApplicationXWwwFormUrlencoded(
     DictSchema
 ):
     _required_property_names = set((
-        'param',
-        'param2',
     ))
     param = StrSchema
     param2 = StrSchema
@@ -83,16 +81,12 @@ class SchemaForRequestBodyApplicationXWwwFormUrlencoded(
     def __new__(
         cls,
         *args: typing.Union[dict, frozendict, ],
-        param: param,
-        param2: param2,
         _configuration: typing.Optional[Configuration] = None,
         **kwargs: typing.Type[Schema],
     ) -> 'SchemaForRequestBodyApplicationXWwwFormUrlencoded':
         return super().__new__(
             cls,
             *args,
-            param=param,
-            param2=param2,
             _configuration=_configuration,
             **kwargs,
         )
diff --git a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/upload_file.py b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/upload_file.py
index c8c8a179a5344c17b0beeb7cb29c5ff703e8471b..e308b76b1f2456ea64222161034e76bb27bf09a9 100644
--- a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/upload_file.py
+++ b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api_endpoints/upload_file.py
@@ -75,7 +75,6 @@ class SchemaForRequestBodyMultipartFormData(
     DictSchema
 ):
     _required_property_names = set((
-        'file',
     ))
     additionalMetadata = StrSchema
     file = BinarySchema
@@ -84,7 +83,6 @@ class SchemaForRequestBodyMultipartFormData(
     def __new__(
         cls,
         *args: typing.Union[dict, frozendict, ],
-        file: file,
         additionalMetadata: typing.Union[additionalMetadata, Unset] = unset,
         _configuration: typing.Optional[Configuration] = None,
         **kwargs: typing.Type[Schema],
@@ -92,7 +90,6 @@ class SchemaForRequestBodyMultipartFormData(
         return super().__new__(
             cls,
             *args,
-            file=file,
             additionalMetadata=additionalMetadata,
             _configuration=_configuration,
             **kwargs,
diff --git a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_file_with_required_file.py b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_file_with_required_file.py
index fb1375c1b8a614922e10e1eae12c4d88e6fed9b5..689f54addd2a51099cf131e58d2d35dda82c8adb 100644
--- a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_file_with_required_file.py
+++ b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_file_with_required_file.py
@@ -101,7 +101,6 @@ class SchemaForRequestBodyMultipartFormData(
     DictSchema
 ):
     _required_property_names = set((
-        'requiredFile',
     ))
     additionalMetadata = StrSchema
     requiredFile = BinarySchema
@@ -110,7 +109,6 @@ class SchemaForRequestBodyMultipartFormData(
     def __new__(
         cls,
         *args: typing.Union[dict, frozendict, ],
-        requiredFile: requiredFile,
         additionalMetadata: typing.Union[additionalMetadata, Unset] = unset,
         _configuration: typing.Optional[Configuration] = None,
         **kwargs: typing.Type[Schema],
@@ -118,7 +116,6 @@ class SchemaForRequestBodyMultipartFormData(
         return super().__new__(
             cls,
             *args,
-            requiredFile=requiredFile,
             additionalMetadata=additionalMetadata,
             _configuration=_configuration,
             **kwargs,
diff --git a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_image.py b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_image.py
index 20bb010ae19be459562d145f7d1210809c83766d..70cce044b135472d9d633260bb44dc6a4f33626e 100644
--- a/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_image.py
+++ b/samples/openapi3/client/petstore/python-experimental/petstore_api/api/pet_api_endpoints/upload_image.py
@@ -108,7 +108,6 @@ class SchemaForRequestBodyMultipartFormData(
         cls,
         *args: typing.Union[dict, frozendict, ],
         additionalMetadata: typing.Union[additionalMetadata, Unset] = unset,
-        file: typing.Union[file, Unset] = unset,
         _configuration: typing.Optional[Configuration] = None,
         **kwargs: typing.Type[Schema],
     ) -> 'SchemaForRequestBodyMultipartFormData':
@@ -116,7 +115,6 @@ class SchemaForRequestBodyMultipartFormData(
             cls,
             *args,
             additionalMetadata=additionalMetadata,
-            file=file,
             _configuration=_configuration,
             **kwargs,
         )
diff --git a/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/Types.hs b/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/Types.hs
index 9a4bfb851ec94dda989472860ba4444bfad10b05..7c19368f7c23f85b10a8a468133785b6b2663f90 100644
--- a/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/Types.hs
+++ b/samples/server/petstore/haskell-servant/lib/OpenAPIPetstore/Types.hs
@@ -193,7 +193,6 @@ removeFieldLabelPrefix forParsing prefix =
       , ("<=", "'Less_Than_Or_Equal_To")
       , (">=", "'Greater_Than_Or_Equal_To")
       , ("!=", "'Not_Equal")
-      , ("<>", "'Not_Equal")
       , ("~=", "'Tilde_Equal")
       , ("\\", "'Back_Slash")
       , ("\"", "'Double_Quote")
diff --git a/samples/server/petstore/haskell-yesod/src/OpenAPIPetstore/Types.hs b/samples/server/petstore/haskell-yesod/src/OpenAPIPetstore/Types.hs
index 5e9b72c8facf8f857e86909317469210f50e51a7..7057e0e55dacd472cb4d23eaf27b59bd1da1087d 100644
--- a/samples/server/petstore/haskell-yesod/src/OpenAPIPetstore/Types.hs
+++ b/samples/server/petstore/haskell-yesod/src/OpenAPIPetstore/Types.hs
@@ -163,7 +163,6 @@ removeFieldLabelPrefix forParsing prefix =
       , ("<=", "'Less_Than_Or_Equal_To")
       , (">=", "'Greater_Than_Or_Equal_To")
       , ("!=", "'Not_Equal")
-      , ("<>", "'Not_Equal")
       , ("~=", "'Tilde_Equal")
       , ("\\", "'Back_Slash")
       , ("\"", "'Double_Quote")