diff --git a/requirements.txt b/requirements.txt
index 0ca193c..9d6b9c0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,7 +29,7 @@ numpy==1.14.0
 oauth2client==4.1.2
 pandas==0.23.1
 ply==3.8
-protobuf==3.5.2
+protobuf==3.18.3
 pyad==0.5.20
 pyasn1==0.4.2
 pyasn1-modules==0.2.1