diff --git a/Gemfile.lock b/Gemfile.lock
index 64fe6c0..81d9c23 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -12,7 +12,7 @@ GEM
     coffee-script-source (1.11.1)
     colorator (1.1.0)
     commonmarker (0.23.10)
-    concurrent-ruby (1.2.2)
+    concurrent-ruby (1.3.7)
     dnsruby (1.70.0)
       simpleidn (~> 0.2.1)
     em-websocket (0.5.3)