diff --git a/docs/changelog.rst b/docs/changelog.rst
index c0ce8384..ce84593c 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -18,6 +18,11 @@ To avail of fixes in an unreleased version, please download a ZIP file
 `directly from GitHub <https://github.com/mitogen-hq/mitogen/>`_.
 
 
+In progress (unreleased)
+------------------------
+
+
+
 v0.3.21 (2025-01-20)
 --------------------
 
diff --git a/mitogen/__init__.py b/mitogen/__init__.py
index bbf807dc..7e8cb030 100644
--- a/mitogen/__init__.py
+++ b/mitogen/__init__.py
@@ -35,7 +35,7 @@ be expected. On the slave, it is built dynamically during startup.
 
 
 #: Library version as a tuple.
-__version__ = (0, 3, 21)
+__version__ = (0, 3, 22, 'dev')
 
 
 #: This is :data:`False` in slave contexts. Previously it was used to prevent