diff --git a/Gemfile b/Gemfile
index 35bc968..f3504ab 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,7 +18,7 @@ gem "jbuilder", "~> 2.5"
 gem "jquery-rails"
 gem "kaminari"
 gem "mini_magick"
-gem "puma", "~> 3.11"
+gem "puma", "~> 4.3"
 gem "rails", "~> 5.2.3"
 gem "rubocop", "~> 0.54.0", require: false
 gem "sass-rails", "~> 5.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index 4d77c33..14fe1ee 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -170,7 +170,9 @@ 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_magick (4.9.4)
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
@@ -189,7 +191,8 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (3.1.1)
-    puma (3.12.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -307,7 +310,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mini_magick
   pry-rails
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rubocop (~> 0.54.0)
   sass-rails (~> 5.0)