diff --git a/cooper_api/Gemfile b/cooper_api/Gemfile
index 281e982..7861bdc 100644
--- a/cooper_api/Gemfile
+++ b/cooper_api/Gemfile
@@ -9,7 +9,7 @@ ruby '2.6.3'
 gem 'bootsnap', '>= 1.2', require: false
 gem 'rails', '~> 5.2.0'
 gem 'pg', '>= 0.18', '< 2.0'
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 gem 'jbuilder', '~> 2.5'
 gem 'rack-cors', require: 'rack/cors'
 gem 'devise_token_auth'
diff --git a/cooper_api/Gemfile.lock b/cooper_api/Gemfile.lock
index 39e5c71..6890676 100644
--- a/cooper_api/Gemfile.lock
+++ b/cooper_api/Gemfile.lock
@@ -86,7 +86,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.12.2)
@@ -104,7 +106,8 @@ GEM
       pry (~> 0.10)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    puma (3.12.1)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-cors (1.0.3)
     rack-test (1.1.0)
@@ -192,7 +195,7 @@ DEPENDENCIES
   pg (>= 0.18, < 2.0)
   pry-byebug
   pry-rails
-  puma (~> 3.7)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.0)
   rspec-rails