diff --git a/Gemfile b/Gemfile
index 1e76851..bf8898a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -21,7 +21,7 @@ group :development do
   gem "binding_of_caller"
 end
 
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 gem 'sass-rails'
 gem 'jquery-rails'
 gem 'jquery-ui-rails'
diff --git a/Gemfile.lock b/Gemfile.lock
index 3a24fbf..77af9b8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -168,7 +168,8 @@ GEM
       coderay (~> 1.1)
       method_source (~> 1.0)
     public_suffix (5.0.0)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.6.1)
     rack (2.2.4)
     rack-protection (3.0.4)
@@ -264,7 +265,7 @@ DEPENDENCIES
   omniauth-rails_csrf_protection
   omniauth-twitter
   pg
-  puma (~> 3.0)
+  puma (~> 4.3)
   rails (~> 5.0.0)
   sass-rails
   sqlite3 (~> 1.3, < 1.4)