diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 66be5e417ef9..bfca9438cd50 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,14 @@
 Changelog
 =========
 
+.. _v39-0-0:
+
+39.0.0 - `main`_
+~~~~~~~~~~~~~~~~
+
+.. note:: This version is not yet released and is under active development.
+
+
 .. _v38-0-0:
 
 38.0.0 - 2022-09-06
diff --git a/src/cryptography/__about__.py b/src/cryptography/__about__.py
index 24aeeac1de55..7adbc40005ef 100644
--- a/src/cryptography/__about__.py
+++ b/src/cryptography/__about__.py
@@ -9,7 +9,7 @@
     "__copyright__",
 ]
 
-__version__ = "38.0.0"
+__version__ = "39.0.0.dev1"
 
 __author__ = "The Python Cryptographic Authority and individual contributors"
 __copyright__ = "Copyright 2013-2022 {}".format(__author__)
diff --git a/vectors/cryptography_vectors/__about__.py b/vectors/cryptography_vectors/__about__.py
index e80fa3c1d674..95eb6b9919a8 100644
--- a/vectors/cryptography_vectors/__about__.py
+++ b/vectors/cryptography_vectors/__about__.py
@@ -6,4 +6,4 @@
     "__version__",
 ]
 
-__version__ = "38.0.0"
+__version__ = "39.0.0.dev1"