diff --git a/requirements.txt b/requirements.txt
index 8c73b08..7ecc3a2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ google-api-python-client==1.5.0
 httplib2==0.9.2
 numpy==1.10.4
 oauth2client==2.0.1
-protobuf==3.0.0b2
+protobuf==3.18.3
 urllib3==1.14
 XlsxWriter==0.8.4
 scikit-learn==0.17.1