diff --git a/docker/build/installers/py27_requirements.txt b/docker/build/installers/py27_requirements.txt
index 5f3fc94a2..3b42808bc 100644
--- a/docker/build/installers/py27_requirements.txt
+++ b/docker/build/installers/py27_requirements.txt
@@ -7,7 +7,7 @@ supervisor
 
 # Google infras.
 glog
-protobuf == 3.1
+protobuf == 3.15.0
 python-gflags
 
 # Web utils.