diff --git a/requirements.txt b/requirements.txt
index 928b711..7eb0b71 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 certifi
-protobuf>=3.0.0
+protobuf==3.20.1
 pyformance>=0.3.1
 requests>=2.7.0
 sseclient-py>=1.4