diff --git a/Gemfile.lock b/Gemfile.lock
index e92f178c..ca2443c0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -208,7 +208,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.1.0)
-    puma (3.12.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pusher-client (0.6.2)
       json
       websocket (~> 1.0)