diff --git a/Gemfile b/Gemfile
index 74b524e8..724ae431 100644
--- a/Gemfile
+++ b/Gemfile
@@ -26,7 +26,7 @@ gem 'activeadmin', github: 'activeadmin'
 gem 'inherited_resources', github: 'activeadmin/inherited_resources'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+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 49d1643d..efe0f673 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -192,7 +192,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.3)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-proxy (0.6.5)
@@ -360,7 +361,7 @@ DEPENDENCIES
   pg (= 0.21.0)
   poltergeist
   pry (~> 0.12.2)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2, >= 5.2.2.1)
   rails-controller-testing
   react_on_rails (~> 11.2, >= 11.2.2)