diff --git a/requirements-core.txt b/requirements-core.txt
index 4773592403..f216c91af0 100644
--- a/requirements-core.txt
+++ b/requirements-core.txt
@@ -46,7 +46,7 @@ pyemd
 pyarrow
 
 # ava data format
-protobuf
+protobuf==4.*
 
 # Comparator
 tabulate