diff --git a/dendronet_legacy/requirements.txt b/dendronet_legacy/requirements.txt
index cda78a0..1cbbf03 100644
--- a/dendronet_legacy/requirements.txt
+++ b/dendronet_legacy/requirements.txt
@@ -56,7 +56,7 @@ pickleshare==0.7.4
 Pillow==5.1.0
 pluggy==0.6.0
 prompt-toolkit==1.0.15
-protobuf==3.0.0
+protobuf==3.15.0
 psutil==5.4.2
 py==1.5.2
 pycairo==1.16.2