diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index b6b8f0b0..191e1d7b 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.5.420
+current_version = 0.5.421-dev
 commit = True
 tag = False
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(?:-(?P<release>[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+(?P<build>[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?
diff --git a/setup.cfg b/setup.cfg
index 5f6e5d26..c1a88c9a 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -4,7 +4,7 @@
 # Configuring setup()
 [metadata]
 name = bioversions
-version = 0.5.420
+version = 0.5.421-dev
 description = What's the current version for each biological database?
 long_description = file: README.md
 long_description_content_type = text/markdown
diff --git a/src/bioversions/version.py b/src/bioversions/version.py
index ff956dae..fc690574 100644
--- a/src/bioversions/version.py
+++ b/src/bioversions/version.py
@@ -9,7 +9,7 @@
     "VERSION",
 ]
 
-VERSION = "0.5.420"
+VERSION = "0.5.421-dev"
 
 
 def get_git_hash() -> str: