diff --git a/Gemfile b/Gemfile
index 915ed5c..c7e02f8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,7 +13,7 @@ gem 'jwt-multisig',                     '~> 1.0'
 gem 'memoist',                          '~> 0.16'
 gem 'mini_racer',                       '~> 0.1', require: false
 gem 'mysql2',                           '>= 0.3.18', '< 0.5'
-gem 'puma',                             '~> 3.7'
+gem 'puma',                             '~> 4.3'
 gem 'rails',                            '~> 5.2'
 gem 'sass-rails',                       '~> 5.0'
 gem 'uglifier',                         '~> 4.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index 356adb2..ab11719 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -131,7 +131,9 @@ GEM
       mimemagic (~> 0.3.2)
     memoist (0.16.0)
     method_source (0.9.0)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.0)
     mini_portile2 (2.3.0)
     mini_racer (0.1.15)
@@ -157,7 +159,8 @@ GEM
       byebug (~> 10.0)
       pry (~> 0.10)
     public_suffix (3.0.2)
-    puma (3.11.4)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.5)
     rack-accept (0.4.5)
       rack (>= 0.4)
@@ -291,7 +294,7 @@ DEPENDENCIES
   mini_racer (~> 0.1)
   mysql2 (>= 0.3.18, < 0.5)
   pry-byebug (~> 3.5)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.2)
   rspec-rails (~> 3.7)
   rubocop (~> 0.55)