diff --git a/requirements.txt b/requirements.txt
index de33b6c..1acfd36 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ chardet==3.0.4
 gtfs-realtime-bindings==0.0.5
 idna==2.6
 pkg-resources==0.0.0
-protobuf==3.5.2
+protobuf==3.18.3
 psycopg2==2.7.4
 requests==2.18.4
 six==1.11.0