diff --git a/Gemfile b/Gemfile
index 37ec6cb..921af22 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 ruby '2.6.6'
 
 gem 'rails', '~> 5.2.4', '>= 5.2.4.3'
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 0e597bf..14988df 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,8 +8,12 @@ GIT
       mutant (~> 0.9.0)
 
 GEM
-  remote: https://rubygems.org/
   remote: https://oss:7AXfeZdAfCqL1PvHm2nvDJO6Zd9UW8IK@gem.mutant.dev/
+  specs:
+    mutant-license (0.1.0)
+
+GEM
+  remote: https://rubygems.org/
   specs:
     abstract_type (0.0.7)
     actioncable (5.2.4.3)
@@ -190,7 +194,6 @@ GEM
       procto (~> 0.0.2)
       unparser (~> 0.4.6)
       variable (~> 0.0.1)
-    mutant-license (0.1.0)
     nio4r (2.5.2)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
@@ -202,7 +205,8 @@ GEM
       coderay (~> 1.1)
       method_source (~> 1.0)
     public_suffix (4.0.5)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-protection (2.0.8.1)
       rack
@@ -347,7 +351,7 @@ DEPENDENCIES
   mutant-minitest!
   pg
   pry
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4, >= 5.2.4.3)
   rails_event_store (~> 1.0.0)
   sass-rails (~> 5.0)