diff --git a/Gemfile b/Gemfile
index 860d0e4..c751a7f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ ruby '2.5.1'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.3'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 18f7948..328b12f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -113,7 +113,9 @@ 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 (5.13.0)
@@ -125,7 +127,8 @@ GEM
     pg (1.1.4)
     popper_js (1.14.5)
     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)
@@ -275,7 +278,7 @@ DEPENDENCIES
   jquery-rails
   listen (>= 3.0.5, < 3.2)
   pg
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rspec-rails
   rspec_junit_formatter