diff --git a/Gemfile b/Gemfile
index d921984..0cd20f5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ ruby '2.5.3'
 
 gem 'rails', '~> 5.2.1'
 gem 'sqlite3'
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 2def2ff..47288be 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -117,7 +117,9 @@ GEM
     marcel (0.3.3)
       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 (2.3.0)
     minitest (5.11.3)
@@ -129,7 +131,8 @@ GEM
     orm_adapter (0.5.0)
     popper_js (1.14.5)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.6)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -236,7 +239,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   jquery-rails
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.1)
   sass-rails (~> 5.0)
   selenium-webdriver