diff --git a/Gemfile b/Gemfile
index 4a7bb280..fc154ca0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -18,7 +18,7 @@ gem 'coffee-rails', '4.2.2'
 gem 'jbuilder',     '2.7.0'
 gem 'jquery-rails', '4.3.1'
 gem 'mysql2'
-gem 'puma', '3.9.1'
+gem 'puma', '4.3.8'
 gem 'sass-rails', '5.0.6'
 gem 'therubyracer'
 gem 'turbolinks', '5.0.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index ff2edb71..288b2c84 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -263,7 +263,9 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.0331)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_magick (4.9.4)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
@@ -298,7 +300,8 @@ GEM
       yard (~> 0.9.11)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    puma (3.9.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -431,7 +434,7 @@ DEPENDENCIES
   pry-byebug
   pry-doc
   pry-rails
-  puma (= 3.9.1)
+  puma (= 4.3.8)
   rails (= 5.2.2)
   rails-controller-testing (= 1.0.2)
   railties (= 5.2.2)