diff --git a/Gemfile.lock b/Gemfile.lock
index 29a15f0..dc794ed 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -14,7 +14,7 @@ GEM
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    concurrent-ruby (1.1.9)
+    concurrent-ruby (1.3.7)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)