diff --git a/transactid/requirements.txt b/transactid/requirements.txt
index 397433b..924ef21 100644
--- a/transactid/requirements.txt
+++ b/transactid/requirements.txt
@@ -1,2 +1,2 @@
 cryptography==2.7
-protobuf==3.9.2
+protobuf==3.15.0