diff --git a/Gemfile b/Gemfile
index 97cbf15..f37eb9d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ ruby '2.6.3'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # use mongo as database
 gem 'mongoid', '~> 6.4.0'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
diff --git a/Gemfile.lock b/Gemfile.lock
index 1493593..b8cc1a2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -84,7 +84,9 @@ 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 (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
@@ -110,8 +112,10 @@ GEM
     octokit (4.14.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     public_suffix (3.1.1)
-    puma (3.12.6)
-    puma (3.12.6-java)
+    puma (4.3.11)
+      nio4r (~> 2.0)
+    puma (4.3.11-java)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-cors (1.0.5)
       rack (>= 1.6.0)
@@ -205,7 +209,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mongoid (~> 6.4.0)
   octokit (~> 4.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.0)
   rspec-rails (>= 3.5.0)