diff --git a/Surrogate_MBO/requirements.txt b/Surrogate_MBO/requirements.txt
index 3b02b4b..ce88151 100644
--- a/Surrogate_MBO/requirements.txt
+++ b/Surrogate_MBO/requirements.txt
@@ -89,7 +89,7 @@ pip-autoremove==0.9.1
 pluggy==0.13.1
 prometheus-client==0.7.1
 prompt-toolkit==2.0.10
-protobuf==3.11.3
+protobuf==3.18.3
 psutil==5.7.0
 ptyprocess==0.6.0
 py==1.8.1