diff --git a/requirements.txt b/requirements.txt
index 328af89..fdeffaf 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ mido==1.2.9
 music21==5.7.1
 numpy==1.17.4
 pretty-midi==0.2.8
-protobuf==3.11.0
+protobuf==3.15.0
 pypianoroll==0.5.2
 scipy==1.3.3
 six==1.13.0