diff --git a/Gemfile b/Gemfile
index 83eb206f..271d00ff 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ source 'https://rubygems.org'
 gem 'rails', '~> 5.2.3'
 gem 'bootstrap-sass', '~> 3.4.1'
 gem 'bcrypt',         '3.1.12'
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'
 gem 'coffee-rails', '~> 4.2'
diff --git a/Gemfile.lock b/Gemfile.lock
index 930650b5..48193543 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -152,7 +152,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.1.1)
-    puma (3.12.1)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -273,7 +274,7 @@ DEPENDENCIES
   minitest (= 5.10.3)
   minitest-reporters (= 1.1.14)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rails-controller-testing (= 1.0.2)
   sass-rails (~> 5.0)