diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,5 +2,6 @@
 click
 py4j
 psutil
+protobuf != 4.21.*  # https://github.com/protocolbuffers/protobuf/issues/10151
 grpcio-tools
 mypy-protobuf