diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index 254387d6b..ec3536555 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 3.21.dev
+current_version = 3.22.dev
 commit = True
 tag = False
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<release>[a-z]+)?(?P<patch>\d+)?
diff --git a/setup.py b/setup.py
index 58f7480aa..9054f7942 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,7 @@
 
 # Static version number which is updated by bump2version
 # Do not change this manually - use 'bump2version <major/minor/patch/release>'
-__version_tag__ = "3.21.dev"
+__version_tag__ = "3.22.dev"
 
 setup_kwargs = {
     "name": "dxtbx",