diff --git a/CHANGELOG.md b/CHANGELOG.md
index a7859f80e..a6999bc71 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,18 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## [0.24.0] - 2022-06-02
+### Fixed
+- Upgraded dependencies
+- Escape reserved keywords in schema names (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1192)
+- Fix pattern single quote escaping (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1275)
+- Fix undefined request body when body is a valid JSON falsy value: false or 0, "". (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1076)
+### Added
+- Add model postfix (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1141)
+- Support free-form objects (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1165)
+- Set default providedIn to root for angular client (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1250)
+- Add json support for application/problem+json content type (https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1208)
+
 ## [0.23.0] - 2022-06-02
 ### Fixed
 - Upgraded dependencies
diff --git a/README.md b/README.md
index 429f905ee..1c9aab97a 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,11 @@
 # OpenAPI Typescript Codegen
 
+This is a Fork of [openapi-typescript-codegen](https://www.npmjs.com/package/openapi-typescript-codegen) with the following changes:
+
+- Merge of https://github.com/ferdikoomen/openapi-typescript-codegen/pull/1145
+
+---
+
 [![NPM][npm-image]][npm-url]
 [![License][license-image]][license-url]
 [![Coverage][coverage-image]][coverage-url]
diff --git a/package-lock.json b/package-lock.json
index 77d207312..944641346 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
     "name": "openapi-typescript-codegen",
-    "version": "0.23.0",
+    "version": "0.24.0",
     "lockfileVersion": 2,
     "requires": true,
     "packages": {
         "": {
             "name": "openapi-typescript-codegen",
-            "version": "0.23.0",
+            "version": "0.24.0",
             "license": "MIT",
             "dependencies": {
                 "camelcase": "^6.3.0",
diff --git a/package.json b/package.json
index cc38c8d10..f893287d4 100644
--- a/package.json
+++ b/package.json
@@ -1,12 +1,12 @@
 {
-    "name": "openapi-typescript-codegen",
-    "version": "0.23.0",
+    "name": "@jshmrtn/openapi-typescript-codegen",
+    "version": "0.24.0",
     "description": "Library that generates Typescript clients based on the OpenAPI specification.",
     "author": "Ferdi Koomen",
-    "homepage": "https://github.com/ferdikoomen/openapi-typescript-codegen",
+    "homepage": "https://github.com/jshmrtn/openapi-typescript-codegen",
     "repository": {
         "type": "git",
-        "url": "git+https://github.com/ferdikoomen/openapi-typescript-codegen.git"
+        "url": "git+https://github.com/jshmrtn/openapi-typescript-codegen.git"
     },
     "bugs": {
         "url": "https://github.com/ferdikoomen/openapi-typescript-codegen/issues"
@@ -29,6 +29,10 @@
         {
             "name": "Ferdi Koomen",
             "email": "info@madebyferdi.com"
+        },
+        {
+            "name": "Jeremy Zahner",
+            "email": "zahner@joshmartin.ch"
         }
     ],
     "main": "dist/index.js",
@@ -56,7 +60,10 @@
         "eslint": "eslint .",
         "eslint:fix": "eslint . --fix",
         "prepublishOnly": "npm run clean && npm run release",
-        "codecov": "codecov --token=66c30c23-8954-4892-bef9-fbaed0a2e42b"
+        "codecov": "codecov --token=66c30c23-8954-4892-bef9-fbaed0a2e42b",
+        "preversion": "npm run test && npm run eslint",
+        "version": "npm run prepublishOnly && git add CHANGELOG.md",
+        "postversion": "git push && git push --tags"
     },
     "dependencies": {
         "camelcase": "^6.3.0",
@@ -120,7 +127,7 @@
         "typescript": "4.8.4",
         "zone.js": "0.11.8"
     },
-    "overrides" : {
+    "overrides": {
         "rollup": "3.2.3"
     }
 }
diff --git a/src/templates/core/utils/OmitReadonly.hbs b/src/templates/core/utils/OmitReadonly.hbs
new file mode 100644
index 000000000..0b6126a31
--- /dev/null
+++ b/src/templates/core/utils/OmitReadonly.hbs
@@ -0,0 +1,47 @@
+/**
+ * The contents of this file are inspired from https://github.com/ts-essentials/ts-essentials#ReadonlyKeys
+ *
+ * The MIT License
+ *
+ * Copyright (c) 2018-2019 Chris Kaczor (github.com/krzkaczor)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * */
+
+type Writable<T> = { -readonly [P in keyof T]: T[P] };
+
+type IsEqualConsideringWritability<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2
+    ? true
+    : false;
+
+type IsFullyWritable<T extends object> = IsEqualConsideringWritability<
+	{ [Q in keyof T]: T[Q] },
+	Writable<{ [Q in keyof T]: T[Q] }>
+>;
+
+/** Gets keys of an object which are readonly */
+type ReadonlyKeys<T extends object> = {
+    [P in keyof T]-?: IsFullyWritable<Pick<T, P>> extends true ? never : P;
+}[keyof T];
+
+/**
+ * Exclude keys of an object which are readonly
+ * In case of union types containing types not extending object, type is inferred as-is
+ * */
+export declare type OmitReadonly<T> = T extends object ? Omit<T, ReadonlyKeys<T>> : T;
diff --git a/src/templates/exportService.hbs b/src/templates/exportService.hbs
index d6bccbbeb..bf6c25bf0 100644
--- a/src/templates/exportService.hbs
+++ b/src/templates/exportService.hbs
@@ -30,6 +30,7 @@ import type { BaseHttpRequest } from '../core/BaseHttpRequest';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
 {{/if}}
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 {{#equals @root.httpClient 'angular'}}
 @Injectable({
diff --git a/src/templates/partials/parameters.hbs b/src/templates/partials/parameters.hbs
index 57ab5a7d1..9e23a9190 100644
--- a/src/templates/partials/parameters.hbs
+++ b/src/templates/partials/parameters.hbs
@@ -16,13 +16,13 @@
 {{/if}}
  */
 {{/ifdef}}
-{{{name}}}{{>isRequired}}: {{>type}},
+{{{name}}}{{>isRequired}}: {{>typeWithOmitReadOnly httpMethod=../method}},
 {{/each}}
 }
 {{~else}}
 
 {{#each parameters}}
-{{{name}}}{{>isRequired}}: {{>type}}{{#if default}} = {{{default}}}{{/if}},
+{{{name}}}{{>isRequired}}: {{>typeWithOmitReadOnly httpMethod=../method}}{{#if default}} = {{{default}}}{{/if}},
 {{/each}}
 {{/if}}
 {{/if}}
diff --git a/src/templates/partials/typeWithOmitReadOnly.hbs b/src/templates/partials/typeWithOmitReadOnly.hbs
new file mode 100644
index 000000000..ec5359c59
--- /dev/null
+++ b/src/templates/partials/typeWithOmitReadOnly.hbs
@@ -0,0 +1,13 @@
+{{#equals export "reference"}}
+{{#equals httpMethod "POST"~}}
+	OmitReadonly<{{>type}}>
+{{~else equals  httpMethod "PUT"~}}
+	OmitReadonly<{{>type}}>
+{{~else equals  httpMethod "PATCH"~}}
+	OmitReadonly<{{>type}}>
+{{else}}
+	{{~>type}}
+{{~/equals}}
+{{~else}}
+	{{~>type}}
+{{~/equals}}
diff --git a/src/utils/registerHandlebarTemplates.ts b/src/utils/registerHandlebarTemplates.ts
index bf77cbdc1..6ead3a7f7 100644
--- a/src/utils/registerHandlebarTemplates.ts
+++ b/src/utils/registerHandlebarTemplates.ts
@@ -46,6 +46,7 @@ import nodeRequest from '../templates/core/node/request.hbs';
 import nodeSendRequest from '../templates/core/node/sendRequest.hbs';
 import templateCoreSettings from '../templates/core/OpenAPI.hbs';
 import templateCoreRequest from '../templates/core/request.hbs';
+import omitReadonly from '../templates/core/utils/OmitReadonly.hbs';
 import xhrGetHeaders from '../templates/core/xhr/getHeaders.hbs';
 import xhrGetRequestBody from '../templates/core/xhr/getRequestBody.hbs';
 import xhrGetResponseBody from '../templates/core/xhr/getResponseBody.hbs';
@@ -83,6 +84,7 @@ import partialTypeInterface from '../templates/partials/typeInterface.hbs';
 import partialTypeIntersection from '../templates/partials/typeIntersection.hbs';
 import partialTypeReference from '../templates/partials/typeReference.hbs';
 import partialTypeUnion from '../templates/partials/typeUnion.hbs';
+import typeWithOmitReadOnly from '../templates/partials/typeWithOmitReadOnly.hbs';
 import { registerHandlebarHelpers } from './registerHandlebarHelpers';
 
 export interface Templates {
@@ -102,6 +104,9 @@ export interface Templates {
         request: Handlebars.TemplateDelegate;
         baseHttpRequest: Handlebars.TemplateDelegate;
         httpRequest: Handlebars.TemplateDelegate;
+        utils: {
+            omitReadonly: Handlebars.TemplateDelegate;
+        };
     };
 }
 
@@ -134,6 +139,9 @@ export const registerHandlebarTemplates = (root: {
             request: Handlebars.template(templateCoreRequest),
             baseHttpRequest: Handlebars.template(templateCoreBaseHttpRequest),
             httpRequest: Handlebars.template(templateCoreHttpRequest),
+            utils: {
+                omitReadonly: Handlebars.template(omitReadonly),
+            },
         },
     };
 
@@ -163,6 +171,7 @@ export const registerHandlebarTemplates = (root: {
     Handlebars.registerPartial('typeInterface', Handlebars.template(partialTypeInterface));
     Handlebars.registerPartial('typeReference', Handlebars.template(partialTypeReference));
     Handlebars.registerPartial('typeUnion', Handlebars.template(partialTypeUnion));
+    Handlebars.registerPartial('typeWithOmitReadOnly', Handlebars.template(typeWithOmitReadOnly));
     Handlebars.registerPartial('typeIntersection', Handlebars.template(partialTypeIntersection));
     Handlebars.registerPartial('base', Handlebars.template(partialBase));
 
diff --git a/src/utils/writeClient.spec.ts b/src/utils/writeClient.spec.ts
index 3c06a95a5..bd2f744ee 100644
--- a/src/utils/writeClient.spec.ts
+++ b/src/utils/writeClient.spec.ts
@@ -33,6 +33,9 @@ describe('writeClient', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/src/utils/writeClient.ts b/src/utils/writeClient.ts
index cea2f3d88..f93179719 100644
--- a/src/utils/writeClient.ts
+++ b/src/utils/writeClient.ts
@@ -52,6 +52,7 @@ export const writeClient = async (
 ): Promise<void> => {
     const outputPath = resolve(process.cwd(), output);
     const outputPathCore = resolve(outputPath, 'core');
+    const outputPathCoreUtils = resolve(outputPath, 'core', 'utils');
     const outputPathModels = resolve(outputPath, 'models');
     const outputPathSchemas = resolve(outputPath, 'schemas');
     const outputPathServices = resolve(outputPath, 'services');
@@ -62,8 +63,17 @@ export const writeClient = async (
 
     if (exportCore) {
         await rmdir(outputPathCore);
-        await mkdir(outputPathCore);
-        await writeClientCore(client, templates, outputPathCore, httpClient, indent, clientName, request);
+        await mkdir(outputPathCoreUtils);
+        await writeClientCore(
+            client,
+            templates,
+            outputPathCore,
+            outputPathCoreUtils,
+            httpClient,
+            indent,
+            clientName,
+            request
+        );
     }
 
     if (exportServices) {
diff --git a/src/utils/writeClientClass.spec.ts b/src/utils/writeClientClass.spec.ts
index 102f2eb57..9233dc4e5 100644
--- a/src/utils/writeClientClass.spec.ts
+++ b/src/utils/writeClientClass.spec.ts
@@ -33,6 +33,9 @@ describe('writeClientClass', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/src/utils/writeClientCore.spec.ts b/src/utils/writeClientCore.spec.ts
index 36990054e..c3eef6856 100644
--- a/src/utils/writeClientCore.spec.ts
+++ b/src/utils/writeClientCore.spec.ts
@@ -35,10 +35,13 @@ describe('writeClientCore', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
-        await writeClientCore(client, templates, '/', HttpClient.FETCH, Indent.SPACE_4);
+        await writeClientCore(client, templates, '/', '/utils', HttpClient.FETCH, Indent.SPACE_4);
 
         expect(writeFile).toBeCalledWith('/OpenAPI.ts', `settings${EOL}`);
         expect(writeFile).toBeCalledWith('/ApiError.ts', `apiError${EOL}`);
@@ -46,5 +49,6 @@ describe('writeClientCore', () => {
         expect(writeFile).toBeCalledWith('/ApiResult.ts', `apiResult${EOL}`);
         expect(writeFile).toBeCalledWith('/CancelablePromise.ts', `cancelablePromise${EOL}`);
         expect(writeFile).toBeCalledWith('/request.ts', `request${EOL}`);
+        expect(writeFile).toBeCalledWith('/utils/OmitReadonly.ts', `omitReadonly${EOL}`);
     });
 });
diff --git a/src/utils/writeClientCore.ts b/src/utils/writeClientCore.ts
index 6d35849d2..74547335f 100644
--- a/src/utils/writeClientCore.ts
+++ b/src/utils/writeClientCore.ts
@@ -14,6 +14,7 @@ import type { Templates } from './registerHandlebarTemplates';
  * @param client Client object, containing, models, schemas and services
  * @param templates The loaded handlebar templates
  * @param outputPath Directory to write the generated files to
+ * @param outputUtilsPath Directory to write the generated util files to
  * @param httpClient The selected httpClient (fetch, xhr, node or axios)
  * @param indent Indentation options (4, 2 or tab)
  * @param clientName Custom client class name
@@ -23,6 +24,7 @@ export const writeClientCore = async (
     client: Client,
     templates: Templates,
     outputPath: string,
+    outputUtilsPath: string,
     httpClient: HttpClient,
     indent: Indent,
     clientName?: string,
@@ -43,6 +45,7 @@ export const writeClientCore = async (
     await writeFile(resolve(outputPath, 'ApiResult.ts'), i(templates.core.apiResult(context), indent));
     await writeFile(resolve(outputPath, 'CancelablePromise.ts'), i(templates.core.cancelablePromise(context), indent));
     await writeFile(resolve(outputPath, 'request.ts'), i(templates.core.request(context), indent));
+    await writeFile(resolve(outputUtilsPath, 'OmitReadonly.ts'), i(templates.core.utils.omitReadonly(context), indent));
 
     if (isDefined(clientName)) {
         await writeFile(resolve(outputPath, 'BaseHttpRequest.ts'), i(templates.core.baseHttpRequest(context), indent));
diff --git a/src/utils/writeClientIndex.spec.ts b/src/utils/writeClientIndex.spec.ts
index a74421115..53d34df12 100644
--- a/src/utils/writeClientIndex.spec.ts
+++ b/src/utils/writeClientIndex.spec.ts
@@ -31,6 +31,9 @@ describe('writeClientIndex', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/src/utils/writeClientModels.spec.ts b/src/utils/writeClientModels.spec.ts
index e147c8e73..611c723ee 100644
--- a/src/utils/writeClientModels.spec.ts
+++ b/src/utils/writeClientModels.spec.ts
@@ -48,6 +48,9 @@ describe('writeClientModels', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/src/utils/writeClientSchemas.spec.ts b/src/utils/writeClientSchemas.spec.ts
index f71286232..af6397f53 100644
--- a/src/utils/writeClientSchemas.spec.ts
+++ b/src/utils/writeClientSchemas.spec.ts
@@ -48,6 +48,9 @@ describe('writeClientSchemas', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/src/utils/writeClientServices.spec.ts b/src/utils/writeClientServices.spec.ts
index b7ebbfe6c..835f3f08b 100644
--- a/src/utils/writeClientServices.spec.ts
+++ b/src/utils/writeClientServices.spec.ts
@@ -36,6 +36,9 @@ describe('writeClientServices', () => {
                 request: () => 'request',
                 baseHttpRequest: () => 'baseHttpRequest',
                 httpRequest: () => 'httpRequest',
+                utils: {
+                    omitReadonly: () => 'omitReadonly',
+                },
             },
         };
 
diff --git a/test/__snapshots__/index.spec.ts.snap b/test/__snapshots__/index.spec.ts.snap
index eefa4ffe0..791dafae9 100644
--- a/test/__snapshots__/index.spec.ts.snap
+++ b/test/__snapshots__/index.spec.ts.snap
@@ -540,6 +540,57 @@ export const request = <T>(config: OpenAPIConfig, options: ApiRequestOptions): C
 "
 `;
 
+exports[`v2 should generate: ./test/generated/v2/core/utils/OmitReadonly.ts 1`] = `
+"/**
+ * The contents of this file are inspired from https://github.com/ts-essentials/ts-essentials#ReadonlyKeys
+ *
+ * The MIT License
+ *
+ * Copyright (c) 2018-2019 Chris Kaczor (github.com/krzkaczor)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * */
+
+type Writable<T> = { -readonly [P in keyof T]: T[P] };
+
+type IsEqualConsideringWritability<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2
+    ? true
+    : false;
+
+type IsFullyWritable<T extends object> = IsEqualConsideringWritability<
+    { [Q in keyof T]: T[Q] },
+    Writable<{ [Q in keyof T]: T[Q] }>
+>;
+
+/** Gets keys of an object which are readonly */
+type ReadonlyKeys<T extends object> = {
+    [P in keyof T]-?: IsFullyWritable<Pick<T, P>> extends true ? never : P;
+}[keyof T];
+
+/**
+ * Exclude keys of an object which are readonly
+ * In case of union types containing types not extending object, type is inferred as-is
+ * */
+export declare type OmitReadonly<T> = T extends object ? Omit<T, ReadonlyKeys<T>> : T;
+"
+`;
+
 exports[`v2 should generate: ./test/generated/v2/index.ts 1`] = `
 "/* istanbul ignore file */
 /* tslint:disable */
@@ -2284,6 +2335,7 @@ exports[`v2 should generate: ./test/generated/v2/services/CollectionFormatServic
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class CollectionFormatService {
 
@@ -2328,6 +2380,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ComplexService {
 
@@ -2372,6 +2425,7 @@ exports[`v2 should generate: ./test/generated/v2/services/DefaultService.ts 1`]
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DefaultService {
 
@@ -2398,6 +2452,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DefaultsService {
 
@@ -2444,7 +2499,7 @@ export class DefaultsService {
         parameterNumber: number = 123,
         parameterBoolean: boolean = true,
         parameterEnum: 'Success' | 'Warning' | 'Error' = 'Success',
-        parameterModel: ModelWithString = {
+        parameterModel: OmitReadonly<ModelWithString> = {
             "prop": "Hello World!"
         },
     ): CancelablePromise<void> {
@@ -2509,6 +2564,7 @@ exports[`v2 should generate: ./test/generated/v2/services/DescriptionsService.ts
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DescriptionsService {
 
@@ -2557,6 +2613,7 @@ exports[`v2 should generate: ./test/generated/v2/services/DuplicateService.ts 1`
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DuplicateService {
 
@@ -2611,6 +2668,7 @@ exports[`v2 should generate: ./test/generated/v2/services/ErrorService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ErrorService {
 
@@ -2648,6 +2706,7 @@ exports[`v2 should generate: ./test/generated/v2/services/HeaderService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class HeaderService {
 
@@ -2678,6 +2737,7 @@ exports[`v2 should generate: ./test/generated/v2/services/MultipleTags1Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags1Service {
 
@@ -2714,6 +2774,7 @@ exports[`v2 should generate: ./test/generated/v2/services/MultipleTags2Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags2Service {
 
@@ -2750,6 +2811,7 @@ exports[`v2 should generate: ./test/generated/v2/services/MultipleTags3Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags3Service {
 
@@ -2775,6 +2837,7 @@ exports[`v2 should generate: ./test/generated/v2/services/NoContentService.ts 1`
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class NoContentService {
 
@@ -2800,6 +2863,7 @@ exports[`v2 should generate: ./test/generated/v2/services/ParametersService.ts 1
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ParametersService {
 
@@ -2895,6 +2959,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ResponseService {
 
@@ -2959,6 +3024,7 @@ exports[`v2 should generate: ./test/generated/v2/services/SimpleService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class SimpleService {
 
@@ -3043,6 +3109,7 @@ exports[`v2 should generate: ./test/generated/v2/services/TypesService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class TypesService {
 
@@ -3633,6 +3700,57 @@ export const request = <T>(config: OpenAPIConfig, options: ApiRequestOptions): C
 "
 `;
 
+exports[`v3 should generate: ./test/generated/v3/core/utils/OmitReadonly.ts 1`] = `
+"/**
+ * The contents of this file are inspired from https://github.com/ts-essentials/ts-essentials#ReadonlyKeys
+ *
+ * The MIT License
+ *
+ * Copyright (c) 2018-2019 Chris Kaczor (github.com/krzkaczor)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ * */
+
+type Writable<T> = { -readonly [P in keyof T]: T[P] };
+
+type IsEqualConsideringWritability<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2
+    ? true
+    : false;
+
+type IsFullyWritable<T extends object> = IsEqualConsideringWritability<
+    { [Q in keyof T]: T[Q] },
+    Writable<{ [Q in keyof T]: T[Q] }>
+>;
+
+/** Gets keys of an object which are readonly */
+type ReadonlyKeys<T extends object> = {
+    [P in keyof T]-?: IsFullyWritable<Pick<T, P>> extends true ? never : P;
+}[keyof T];
+
+/**
+ * Exclude keys of an object which are readonly
+ * In case of union types containing types not extending object, type is inferred as-is
+ * */
+export declare type OmitReadonly<T> = T extends object ? Omit<T, ReadonlyKeys<T>> : T;
+"
+`;
+
 exports[`v3 should generate: ./test/generated/v3/index.ts 1`] = `
 "/* istanbul ignore file */
 /* tslint:disable */
@@ -6274,6 +6392,7 @@ exports[`v3 should generate: ./test/generated/v3/services/CollectionFormatServic
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class CollectionFormatService {
 
@@ -6321,6 +6440,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ComplexService {
 
@@ -6398,6 +6518,7 @@ exports[`v3 should generate: ./test/generated/v3/services/DefaultService.ts 1`]
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DefaultService {
 
@@ -6424,6 +6545,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DefaultsService {
 
@@ -6470,7 +6592,7 @@ export class DefaultsService {
         parameterNumber: number = 123,
         parameterBoolean: boolean = true,
         parameterEnum: 'Success' | 'Warning' | 'Error' = 'Success',
-        parameterModel: ModelWithString = {
+        parameterModel: OmitReadonly<ModelWithString> = {
             "prop": "Hello World!"
         },
     ): CancelablePromise<void> {
@@ -6537,6 +6659,7 @@ import type { DeprecatedModel } from '../models/DeprecatedModel';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DeprecatedService {
 
@@ -6546,7 +6669,7 @@ export class DeprecatedService {
      * @throws ApiError
      */
     public static deprecatedCall(
-        parameter: DeprecatedModel | null,
+        parameter: OmitReadonly<DeprecatedModel | null>,
     ): CancelablePromise<void> {
         return __request(OpenAPI, {
             method: 'POST',
@@ -6568,6 +6691,7 @@ exports[`v3 should generate: ./test/generated/v3/services/DescriptionsService.ts
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DescriptionsService {
 
@@ -6616,6 +6740,7 @@ exports[`v3 should generate: ./test/generated/v3/services/DuplicateService.ts 1`
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class DuplicateService {
 
@@ -6670,6 +6795,7 @@ exports[`v3 should generate: ./test/generated/v3/services/ErrorService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ErrorService {
 
@@ -6709,6 +6835,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class FormDataService {
 
@@ -6719,7 +6846,7 @@ export class FormDataService {
      */
     public static postApiFormData(
         parameter?: string,
-        formData?: ModelWithString,
+        formData?: OmitReadonly<ModelWithString>,
     ): CancelablePromise<void> {
         return __request(OpenAPI, {
             method: 'POST',
@@ -6743,6 +6870,7 @@ exports[`v3 should generate: ./test/generated/v3/services/HeaderService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class HeaderService {
 
@@ -6775,6 +6903,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipartService {
 
@@ -6824,6 +6953,7 @@ exports[`v3 should generate: ./test/generated/v3/services/MultipleTags1Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags1Service {
 
@@ -6860,6 +6990,7 @@ exports[`v3 should generate: ./test/generated/v3/services/MultipleTags2Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags2Service {
 
@@ -6896,6 +7027,7 @@ exports[`v3 should generate: ./test/generated/v3/services/MultipleTags3Service.t
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class MultipleTags3Service {
 
@@ -6921,6 +7053,7 @@ exports[`v3 should generate: ./test/generated/v3/services/NoContentService.ts 1`
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class NoContentService {
 
@@ -6949,6 +7082,7 @@ import type { Pageable } from '../models/Pageable';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ParametersService {
 
@@ -6967,7 +7101,7 @@ export class ParametersService {
         parameterForm: string | null,
         parameterCookie: string | null,
         parameterPath: string | null,
-        requestBody: ModelWithString | null,
+        requestBody: OmitReadonly<ModelWithString | null>,
     ): CancelablePromise<void> {
         return __request(OpenAPI, {
             method: 'POST',
@@ -7009,7 +7143,7 @@ export class ParametersService {
         parameterQuery: string | null,
         parameterForm: string | null,
         parameterCookie: string | null,
-        requestBody: ModelWithString | null,
+        requestBody: OmitReadonly<ModelWithString | null>,
         parameterPath1?: string,
         parameterPath2?: string,
         parameterPath3?: string,
@@ -7067,8 +7201,8 @@ export class ParametersService {
      * @throws ApiError
      */
     public static postCallWithOptionalParam(
-        parameter: Pageable,
-        requestBody?: ModelWithString,
+        parameter: OmitReadonly<Pageable>,
+        requestBody?: OmitReadonly<ModelWithString>,
     ): CancelablePromise<void> {
         return __request(OpenAPI, {
             method: 'POST',
@@ -7094,6 +7228,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class RequestBodyService {
 
@@ -7104,7 +7239,7 @@ export class RequestBodyService {
      */
     public static postApiRequestBody(
         parameter?: string,
-        requestBody?: ModelWithString,
+        requestBody?: OmitReadonly<ModelWithString>,
     ): CancelablePromise<void> {
         return __request(OpenAPI, {
             method: 'POST',
@@ -7132,6 +7267,7 @@ import type { ModelWithString } from '../models/ModelWithString';
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class ResponseService {
 
@@ -7196,6 +7332,7 @@ exports[`v3 should generate: ./test/generated/v3/services/SimpleService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class SimpleService {
 
@@ -7280,6 +7417,7 @@ exports[`v3 should generate: ./test/generated/v3/services/TypesService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class TypesService {
 
@@ -7337,6 +7475,7 @@ exports[`v3 should generate: ./test/generated/v3/services/UploadService.ts 1`] =
 import type { CancelablePromise } from '../core/CancelablePromise';
 import { OpenAPI } from '../core/OpenAPI';
 import { request as __request } from '../core/request';
+import type { OmitReadonly } from '../core/utils/OmitReadonly';
 
 export class UploadService {