diff --git a/Gemfile b/Gemfile
index dc1dead..641ff74 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.2'
 # Use sqlite3 as the database for Active Record
 # gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+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 aea8597..47d6276 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -116,7 +116,9 @@ 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 (5.11.3)
@@ -149,7 +151,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.3)
-    puma (3.12.4)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -257,7 +260,7 @@ DEPENDENCIES
   omniauth-facebook
   pg
   pry
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   sass-rails (~> 5.0)
   selenium-webdriver