diff --git a/pb/Gemfile.lock b/pb/Gemfile.lock
index 8e5abacb3..2dc14c3cc 100644
--- a/pb/Gemfile.lock
+++ b/pb/Gemfile.lock
@@ -13,4 +13,4 @@ RUBY VERSION
    ruby 2.3.1p112
 
 BUNDLED WITH
-   2.1.4
+   1.17.3