diff --git a/pyproject.toml b/pyproject.toml
index a501af7..83f7a21 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -27,7 +27,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
 ]
 dependencies = [
-  "capellambse>=0.5.39",
+  "capellambse>=0.5.39,<0.6",
   "click",
   "diff-match-patch>=20230430",
   "jinja2>=3.1.2",