diff --git a/Gemfile b/Gemfile
index e9b6b52..c85419f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'jbuilder', '~> 2.5'
 gem 'jquery-rails'
 gem 'less-rails'
 gem 'pg', '>= 0.18', '< 2.0'
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 gem 'rails', '~> 5.2.2'
 gem 'sass-rails', '~> 5.0'
 gem 'simple_form'
diff --git a/Gemfile.lock b/Gemfile.lock
index a0b8899..7f079e2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -118,7 +118,9 @@ 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 (1.0.1)
     mini_portile2 (2.4.0)
     minitest (5.14.0)
@@ -132,7 +134,8 @@ GEM
       ast (~> 2.4.0)
     pg (1.1.3)
     public_suffix (3.0.3)
-    puma (3.12.4)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -259,7 +262,7 @@ DEPENDENCIES
   less-rails
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   rubocop
   sass-rails (~> 5.0)