diff --git a/Gemfile.lock b/Gemfile.lock
index 9f7c592..9fde96d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,7 +6,7 @@ GEM
     base64 (0.3.0)
     bigdecimal (3.2.2)
     colorator (1.1.0)
-    concurrent-ruby (1.1.4)
+    concurrent-ruby (1.3.7)
     csv (3.3.5)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)