diff --git a/requirements.txt b/requirements.txt
index 00aadf7..3d7bd45 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ idna==2.6
 msgpack==0.5.6
 nltk==3.2.5
 numpy==1.14.3
-protobuf==3.5.2.post1
+protobuf==3.15.0
 requests==2.18.4
 scipy==1.1.0
 six==1.11.0