diff --git a/py/BUILD.bazel b/py/BUILD.bazel
index 7028a5680fe32..746e5eaa4a80b 100644
--- a/py/BUILD.bazel
+++ b/py/BUILD.bazel
@@ -40,7 +40,7 @@ compile_pip_requirements(
     ],
 )
 
-SE_VERSION = "4.20.0"
+SE_VERSION = "4.21.0.dev202404242345"
 
 BROWSER_VERSIONS = [
     "v85",
diff --git a/py/docs/source/conf.py b/py/docs/source/conf.py
index a7ebffa2ad1d4..d2bdb487c0a70 100644
--- a/py/docs/source/conf.py
+++ b/py/docs/source/conf.py
@@ -56,9 +56,9 @@
 # built documents.
 #
 # The short X.Y version.
-version = '4.20'
+version = '4.21'
 # The full version, including alpha/beta/rc tags.
-release = '4.20.0'
+release = '4.21.0.dev202404242345'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/py/selenium/__init__.py b/py/selenium/__init__.py
index 182e4d7910096..bc9c37bd212e5 100644
--- a/py/selenium/__init__.py
+++ b/py/selenium/__init__.py
@@ -16,4 +16,4 @@
 # under the License.
 
 
-__version__ = "4.20.0"
+__version__ = "4.21.0.dev202404242345"
diff --git a/py/selenium/webdriver/__init__.py b/py/selenium/webdriver/__init__.py
index 3873e6c56d464..f9304b14f5aa0 100644
--- a/py/selenium/webdriver/__init__.py
+++ b/py/selenium/webdriver/__init__.py
@@ -44,7 +44,7 @@
 from .wpewebkit.service import Service as WPEWebKitService  # noqa
 from .wpewebkit.webdriver import WebDriver as WPEWebKit  # noqa
 
-__version__ = "4.20.0"
+__version__ = "4.21.0.dev202404242345"
 
 # We need an explicit __all__ because the above won't otherwise be exported.
 __all__ = [
diff --git a/py/setup.py b/py/setup.py
index 0e8c107caa3be..14f86dcaa53ba 100755
--- a/py/setup.py
+++ b/py/setup.py
@@ -27,7 +27,7 @@
 setup_args = {
     'cmdclass': {'install': install},
     'name': 'selenium',
-    'version': "4.20.0",
+    'version': "4.21.0.dev202404242345",
     'license': 'Apache 2.0',
     'description': 'Python bindings for Selenium',
     'long_description': open(join(abspath(dirname(__file__)), "README.rst")).read(),