diff --git a/Gemfile b/Gemfile
index c7f11f6..da47286 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 gem 'rails', '~> 5.2.0'
 
 # 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 ff5d60a..b106769 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -154,7 +154,9 @@ GEM
     marcel (0.3.2)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
@@ -168,7 +170,8 @@ GEM
     pg (0.21.0)
     popper_js (1.14.5)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -290,7 +293,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mysql2 (>= 0.4.4, < 0.6.0)
   pg (~> 0.18)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.0)
   sass-rails (~> 5.0)
   seed_dump