diff --git a/kubernetes/README.md b/kubernetes/README.md
index 13f212695..bc6861ad9 100644
--- a/kubernetes/README.md
+++ b/kubernetes/README.md
@@ -4,7 +4,7 @@ No description provided (generated by Openapi Generator https://github.com/opena
 This Python package is automatically generated by the [OpenAPI Generator](https://openapi-generator.tech) project:
 
 - API version: release-1.18
-- Package version: 18.20.0b1
+- Package version: 18.20.0
 - Build package: org.openapitools.codegen.languages.PythonClientCodegen
 
 ## Requirements.
diff --git a/kubernetes/__init__.py b/kubernetes/__init__.py
index 2b367f888..66af35f59 100644
--- a/kubernetes/__init__.py
+++ b/kubernetes/__init__.py
@@ -14,7 +14,7 @@
 
 __project__ = 'kubernetes'
 # The version is auto-updated. Please do not edit.
-__version__ = "18.20.0b1"
+__version__ = "18.20.0"
 
 import kubernetes.client
 import kubernetes.config
diff --git a/kubernetes/client/__init__.py b/kubernetes/client/__init__.py
index b47a5b3da..5f8d5cbd8 100644
--- a/kubernetes/client/__init__.py
+++ b/kubernetes/client/__init__.py
@@ -14,7 +14,7 @@
 
 from __future__ import absolute_import
 
-__version__ = "18.20.0b1"
+__version__ = "18.20.0"
 
 # import apis into sdk package
 from kubernetes.client.api.admissionregistration_api import AdmissionregistrationApi
diff --git a/kubernetes/client/api/custom_objects_api.py b/kubernetes/client/api/custom_objects_api.py
index 2e038a914..613763b59 100644
--- a/kubernetes/client/api/custom_objects_api.py
+++ b/kubernetes/client/api/custom_objects_api.py
@@ -2425,7 +2425,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
@@ -2594,7 +2594,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
@@ -2763,7 +2763,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
@@ -2941,7 +2941,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
@@ -3119,7 +3119,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json', 'application/apply-patch+yaml'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
@@ -3297,7 +3297,7 @@ class CustomObjectsApi(object):
 
         # HTTP header `Content-Type`
         header_params['Content-Type'] = self.api_client.select_header_content_type(  # noqa: E501
-            ['application/merge-patch+json'])  # noqa: E501
+            ['application/json-patch+json', 'application/merge-patch+json', 'application/apply-patch+yaml'])  # noqa: E501
 
         # Authentication setting
         auth_settings = ['BearerToken']  # noqa: E501
diff --git a/kubernetes/client/api_client.py b/kubernetes/client/api_client.py
index edcdead5f..88dc7e038 100644
--- a/kubernetes/client/api_client.py
+++ b/kubernetes/client/api_client.py
@@ -78,7 +78,7 @@ class ApiClient(object):
             self.default_headers[header_name] = header_value
         self.cookie = cookie
         # Set default User-Agent.
-        self.user_agent = 'OpenAPI-Generator/18.20.0b1/python'
+        self.user_agent = 'OpenAPI-Generator/18.20.0/python'
         self.client_side_validation = configuration.client_side_validation
 
     def __enter__(self):
diff --git a/kubernetes/client/apis/__init__.py b/kubernetes/client/apis/__init__.py
deleted file mode 100644
index ca4b321de..000000000
--- a/kubernetes/client/apis/__init__.py
+++ /dev/null
@@ -1,13 +0,0 @@
-from __future__ import absolute_import
-import warnings
-
-# flake8: noqa
-
-# alias kubernetes.client.api package and print deprecation warning
-from kubernetes.client.api import *
-
-warnings.filterwarnings('default', module='kubernetes.client.apis')
-warnings.warn(
-    "The package kubernetes.client.apis is renamed and deprecated, use kubernetes.client.api instead (please note that the trailing s was removed).",
-    DeprecationWarning
-)
diff --git a/kubernetes/client/configuration.py b/kubernetes/client/configuration.py
index ed81b5164..c61c07044 100644
--- a/kubernetes/client/configuration.py
+++ b/kubernetes/client/configuration.py
@@ -347,7 +347,7 @@ class Configuration(object):
                "OS: {env}\n"\
                "Python Version: {pyversion}\n"\
                "Version of the API: release-1.18\n"\
-               "SDK Package Version: 18.20.0b1".\
+               "SDK Package Version: 18.20.0".\
                format(env=sys.platform, pyversion=sys.version)
 
     def get_host_settings(self):
diff --git a/kubernetes/client/models/v1_projected_volume_source.py b/kubernetes/client/models/v1_projected_volume_source.py
index ab8c66a26..a2f41d730 100644
--- a/kubernetes/client/models/v1_projected_volume_source.py
+++ b/kubernetes/client/models/v1_projected_volume_source.py
@@ -99,6 +99,9 @@ class V1ProjectedVolumeSource(object):
         :param sources: The sources of this V1ProjectedVolumeSource.  # noqa: E501
         :type: list[V1VolumeProjection]
         """
+        if self.local_vars_configuration.client_side_validation and sources is None:  # noqa: E501
+            raise ValueError("Invalid value for `sources`, must not be `None`")  # noqa: E501
+
         self._sources = sources
 
     def to_dict(self):
diff --git a/kubernetes/test/test_api_client.py b/kubernetes/test/test_api_client.py
deleted file mode 100644
index f0a9416cf..000000000
--- a/kubernetes/test/test_api_client.py
+++ /dev/null
@@ -1,25 +0,0 @@
-# coding: utf-8
-
-
-import atexit
-import weakref
-import unittest
-
-import kubernetes
-
-
-class TestApiClient(unittest.TestCase):
-
-    def test_context_manager_closes_threadpool(self):
-        with kubernetes.client.ApiClient() as client:
-            self.assertIsNotNone(client.pool)
-            pool_ref = weakref.ref(client._pool)
-            self.assertIsNotNone(pool_ref())
-        self.assertIsNone(pool_ref())
-
-    def test_atexit_closes_threadpool(self):
-        client = kubernetes.client.ApiClient()
-        self.assertIsNotNone(client.pool)
-        self.assertIsNotNone(client._pool)
-        atexit._run_exitfuncs()
-        self.assertIsNone(client._pool)
diff --git a/kubernetes/test/test_configuration.py b/kubernetes/test/test_configuration.py
deleted file mode 100644
index 15e065090..000000000
--- a/kubernetes/test/test_configuration.py
+++ /dev/null
@@ -1,39 +0,0 @@
-# coding: utf-8
-
-import unittest
-
-from kubernetes.client import Configuration
-
-class TestConfiguration(unittest.TestCase):
-
-    def setUp(self):
-        pass
-
-    def tearDown(self):
-        # reset Configuration
-        Configuration.set_default(None)
-
-    def testConfiguration(self):
-        # check that different instances use different dictionaries
-        c1 = Configuration()
-        c2 = Configuration()
-        self.assertNotEqual(id(c1.api_key), id(c2.api_key))
-        self.assertNotEqual(id(c1.api_key_prefix), id(c2.api_key_prefix))
-
-    def testDefaultConfiguration(self):
-        # prepare default configuration
-        c1 = Configuration(host="example.com")
-        c1.debug = True
-        Configuration.set_default(c1)
-
-        # get default configuration
-        c2 = Configuration.get_default_copy()
-        self.assertEqual(c2.host, "example.com")
-        self.assertTrue(c2.debug)
-
-        self.assertNotEqual(id(c1.api_key), id(c2.api_key))
-        self.assertNotEqual(id(c1.api_key_prefix), id(c2.api_key_prefix))
-
-
-if __name__ == '__main__':
-    unittest.main()
diff --git a/setup.py b/setup.py
index 28014ceeb..3c165940f 100644
--- a/setup.py
+++ b/setup.py
@@ -16,9 +16,9 @@ from setuptools import setup
 
 # Do not edit these constants. They will be updated automatically
 # by scripts/update-client.sh.
-CLIENT_VERSION = "18.20.0b1"
+CLIENT_VERSION = "18.20.0"
 PACKAGE_NAME = "kubernetes"
-DEVELOPMENT_STATUS = "4 - Beta"
+DEVELOPMENT_STATUS = "5 - Production/Stable"
 
 # To install the library, run the following
 #