diff --git a/pymongo/__init__.py b/pymongo/__init__.py
index 801d466c2e..62139dac11 100644
--- a/pymongo/__init__.py
+++ b/pymongo/__init__.py
@@ -55,7 +55,7 @@
 .. _text index: http://mongodb.com/docs/manual/core/index-text/
 """
 
-version_tuple: Tuple[Union[int, str], ...] = (4, 2, 0, ".dev1")
+version_tuple: Tuple[Union[int, str], ...] = (4, 2, 0, "b0")
 
 
 def get_version_string() -> str:
diff --git a/setup.py b/setup.py
index 655cc5ea0c..0d77c7c720 100755
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
     except ImportError:
         _HAVE_SPHINX = False
 
-version = "4.2.0.dev1"
+version = "4.2.0b0"
 
 f = open("README.rst")
 try: