diff --git a/Gemfile b/Gemfile
index 82e131b..77999b3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production
diff --git a/Gemfile.lock b/Gemfile.lock
index 464d070..64a6ff6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -78,7 +78,9 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
-    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)
@@ -90,7 +92,8 @@ GEM
     pg (1.1.3)
     postgresql_cursor (0.6.2)
       activerecord (>= 3.1.0)
-    puma (3.12.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.6)
     rack-cors (1.0.2)
     rack-test (1.1.0)
@@ -175,7 +178,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
   postgresql_cursor
-  puma (~> 3.11)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.2)
   rspec-rails (~> 3.8)