diff --git a/pyproject.toml b/pyproject.toml
index b8cd24e7..2edd9828 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -40,7 +40,7 @@ dependencies = [
   "frequenz-channels >= 1.0.0-rc1, < 2.0.0",
   "frequenz-client-base >= 0.8.0, < 0.10.0",
   "grpcio >= 1.54.2, < 2",
-  "protobuf >= 4.21.6, < 6",
+  "protobuf >= 4.21.6, < 7",
   "timezonefinder >= 6.2.0, < 7",
   "typing-extensions >= 4.5.0, < 5",
 ]