diff --git a/Gemfile b/Gemfile
index 70ca31b..1ca76fa 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,7 @@ group :production do
 end
 gem 'net-http-persistent', '~> 2.9', '>= 2.9.4'
 # 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 eed0c3c..de31d6d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -126,7 +126,8 @@ GEM
     pg (1.2.3)
     popper_js (1.16.0)
     public_suffix (4.0.5)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -257,7 +258,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   net-http-persistent (~> 2.9, >= 2.9.4)
   pg
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.4, >= 5.2.4.3)
   rspec-rails
   sass-rails (~> 5.0)