diff --git a/requirements.txt b/requirements.txt
index dda58a9..784d8ff 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -16,6 +16,6 @@
 grpc-robot>=2.9.3
 kafka-robot>=2.3.2
 voltha-protos>=4.2.0
-protobuf>=3.15.7
+protobuf>=3.15.7,<3.20.0
 protobuf3-to-dict>=0.1.5
 device-management-interface>=1.2.1