diff --git a/Gemfile.lock b/Gemfile.lock
index 8f45f4e..660b6e8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,7 +8,7 @@ GEM
       io-event (~> 1.1)
       timers (~> 4.1)
     colorator (1.1.0)
-    concurrent-ruby (1.2.2)
+    concurrent-ruby (1.3.7)
     console (1.16.2)
       fiber-local
     em-websocket (0.5.3)