diff --git a/appengine/standard-static-files/rails/Gemfile.lock b/appengine/standard-static-files/rails/Gemfile.lock
index f07a64b52..0212c8748 100644
--- a/appengine/standard-static-files/rails/Gemfile.lock
+++ b/appengine/standard-static-files/rails/Gemfile.lock
@@ -122,7 +122,7 @@ GEM
     mini_mime (1.1.5)
     mini_portile2 (2.8.8)
     minitest (5.22.2)
-    net-imap (0.4.24)
+    net-imap (0.5.15)
       date
       net-protocol
     net-pop (0.1.2)