diff --git a/pyproject.toml b/pyproject.toml
index d11db8472..77fcb9e2d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ authors = [
   { name = "Volker Hirthammer", email = "volker.hirthammer@bam.de" },
   { name = "Martin K. Scherer", email = "martin.scherer@bam.de" },
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.9,<3.12"
 classifiers = [
   "Development Status :: 4 - Beta",
   "Intended Audience :: Education",