diff --git a/Gemfile.lock b/Gemfile.lock
index 2a17b3f..93ff7cd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -139,7 +139,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.1)
-    puma (3.12.2)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-protection (2.0.7)
       rack