diff --git a/Gemfile b/Gemfile
index 961ee97..787c07d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ ruby '2.5.5'
 
 gem 'rails', '~> 5.2.3'
 gem 'pg'
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Reduces boot times through caching; required in config/boot.rb
 gem 'bootsnap', '>= 1.1.0', require: false
 gem "graphql"
diff --git a/Gemfile.lock b/Gemfile.lock
index cdffb8b..995bd9b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -80,7 +80,9 @@ 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 (5.11.3)
@@ -90,7 +92,8 @@ GEM
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
     public_suffix (3.1.1)
-    puma (3.12.1)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -179,7 +182,7 @@ DEPENDENCIES
   graphql
   listen (>= 3.0.5, < 3.2)
   pg
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rspec-graphql_matchers
   rspec-rails (~> 3.8)