diff --git a/pyproject.toml b/pyproject.toml
index a785f46..fa598cc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,7 +34,7 @@ dependencies = [
     "traitlets>=5.9.0",
 ]
 name = "pyxcp"
-version = "0.21.8"
+version = "0.21.9"
 readme = "README.md"
 description = "Universal Calibration Protocol for Python"
 keywords = ["automotive", "ecu", "xcp", "asam", "autosar"]
diff --git a/pyxcp/__init__.py b/pyxcp/__init__.py
index 8dfd730..e6a9f57 100644
--- a/pyxcp/__init__.py
+++ b/pyxcp/__init__.py
@@ -24,5 +24,5 @@
 from .transport import SxI
 from .transport import Usb
 
-# if you update this manually, do not forget to update .bumpversion.cfg
+# if you update this manually, do not forget to update .bumpversion.cfg and pyproject.toml
 __version__ = "0.21.9"