diff --git a/ipyparallel/_version.py b/ipyparallel/_version.py
index f5ca056f..5c81087b 100644
--- a/ipyparallel/_version.py
+++ b/ipyparallel/_version.py
@@ -1,6 +1,6 @@
 import re
 
-__version__ = "9.0.0"
+__version__ = "9.1.0.dev"
 
 # matches tbump regex in pyproject.toml
 _version_regex = re.compile(
diff --git a/package.json b/package.json
index 1f10d3b6..8d304c09 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ipyparallel-labextension",
-  "version": "9.0.0",
+  "version": "9.1.0",
   "private": true,
   "description": "A JupyterLab extension for IPython Parallel.",
   "keywords": [
diff --git a/pyproject.toml b/pyproject.toml
index 066c9833..8fe98a6b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "ipyparallel"
-version = "9.0.0"
+version = "9.1.0.dev"
 authors = [{name = "IPython Development Team", email = "ipython-dev@scipy.org"}]
 license = {file = "COPYING.md"}
 readme = "README.md"
@@ -183,7 +183,7 @@ select = [
 github_url = "https://github.com/jupyterhub/jupyterhub"
 
 [tool.tbump.version]
-current = "9.0.0"
+current = "9.1.0.dev"
 
 # pep440 regex
 regex = '''