diff --git a/websocket_server/requirements.txt b/websocket_server/requirements.txt
index d343437..0ff4396 100644
--- a/websocket_server/requirements.txt
+++ b/websocket_server/requirements.txt
@@ -24,7 +24,7 @@ numpy==1.14.5
 oauth2client==4.1.3
 oauthlib==3.1.0
 Pillow==7.1.2
-protobuf==3.11.3
+protobuf==3.15.0
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 python-engineio==3.12.1