diff --git a/Gemfile b/Gemfile
index 3b4126f..5791037 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'rails', '~> 5.2.2'
 gem 'pg'
 gem 'mysql2'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index b769620..345163c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -151,7 +151,9 @@ GEM
     mime-types (3.3)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.1009)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_magick (4.9.5)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
@@ -176,7 +178,8 @@ GEM
     pg (1.1.4)
     popper_js (1.14.5)
     public_suffix (4.0.1)
-    puma (3.12.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -312,7 +315,7 @@ DEPENDENCIES
   nokogiri
   paperclip (~> 6.0.0)
   pg
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   remotipart (~> 1.2)
   sass-rails (~> 5.0)