diff --git a/Gemfile b/Gemfile
index 2128cb84..b02811f8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -57,7 +57,7 @@ gem 'rubyzip', '>= 1.0.0'
 # URL validation
 gem 'addressable', '~> 2.5'
 
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 gem 'redis', '~> 3.0'
 
 group :development, :test do
diff --git a/Gemfile.lock b/Gemfile.lock
index 48900dd7..943a2b48 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -210,7 +210,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (3.0.1)
-    puma (3.11.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
     rack (2.0.5)
@@ -417,7 +418,7 @@ DEPENDENCIES
   nicescroll-rails
   omniauth-openid
   pg (~> 0.15)
-  puma (~> 3.7)
+  puma (~> 4.3)
   pundit
   rack-attack
   railroady