diff --git a/Gemfile b/Gemfile
index 84b2cdf..59b8eec 100644
--- a/Gemfile
+++ b/Gemfile
@@ -82,7 +82,7 @@ gem 'actionview', '~> 5.0', '>= 5.0.7.2'
 gem 'ffi', '~> 1.9', '>= 1.9.25'
 gem 'loofah', '~> 2.3', '>= 2.3.1'
 gem 'nokogiri', '~> 1.10', '>= 1.10.8'
-gem 'puma', '~> 3.0', '>= 3.12.5'
+gem 'puma', '~> 4.3'
 gem 'rack', '~> 2.0', '>= 2.1.4'
 gem 'rails-html-sanitizer', '~> 1.0', '>= 1.0.4'
 gem 'rest-client', '~> 1.8', '>= 1.8.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 87557fe..f717bfa 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -162,7 +162,8 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
     public_suffix (4.0.1)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -320,7 +321,7 @@ DEPENDENCIES
   pg (~> 0.18)
   phantomjs
   poltergeist
-  puma (~> 3.0, >= 3.12.5)
+  puma (~> 4.3)
   rack (~> 2.0, >= 2.1.4)
   rails (~> 5.0.0, >= 5.0.0.1)
   rails-controller-testing