diff --git a/appengine/standard-rails-hello-world/Gemfile.lock b/appengine/standard-rails-hello-world/Gemfile.lock
index 96e6c5de4..dca2c104a 100644
--- a/appengine/standard-rails-hello-world/Gemfile.lock
+++ b/appengine/standard-rails-hello-world/Gemfile.lock
@@ -80,7 +80,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
-    concurrent-ruby (1.2.3)
+    concurrent-ruby (1.3.7)
     crass (1.0.6)
     date (3.3.4)
     diff-lcs (1.5.0)