diff --git a/Gemfile b/Gemfile
index 6a08159..6f76c7f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # 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 048b573..8ee7c5c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -84,7 +84,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (1.0.0)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.2)
@@ -96,7 +98,8 @@ GEM
     pry (0.13.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
-    puma (3.12.6)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
@@ -184,7 +187,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   pg (>= 0.18, < 2.0)
   pry (~> 0.13.1)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.3)
   rspec-rails (~> 4.0.1)