diff --git a/requirements.txt b/requirements.txt
index 781c584..e4bd4f1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,7 @@ jws==0.1.3
 numpy==1.13.1
 oauth2client==3.0.0
 pkg-resources==0.0.0
-protobuf==3.4.0
+protobuf==3.15.0
 pyasn1==0.3.3
 pyasn1-modules==0.1.1
 pycryptodome==3.4.3