diff --git a/pyproject.toml b/pyproject.toml
index 3aa493b9..69b10b05 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "ampel-hu-astro"
-version = "0.10.0a3"
+version = "0.10.0a4"
 license = "BSD-3-Clause"
 readme = "README.md"
 description = "Astronomy units for the Ampel system from HU-Berlin"