diff --git a/Gemfile b/Gemfile
index 642e5c7..ace8efe 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,7 @@ gem "i18n-js"
 gem "jbuilder", "~> 2.5"
 gem "jquery-rails", ">= 4.3.3"
 gem "mini_magick", "4.7.0"
-gem "puma", "~> 3.11"
+gem "puma", "~> 4.3"
 gem "rails-controller-testing"
 gem "rails-i18n"
 gem "rails-ujs", "~> 0.1.0"
diff --git a/Gemfile.lock b/Gemfile.lock
index 59b312a..062fa2f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -170,7 +170,8 @@ GEM
     pg (1.1.4)
     powerpack (0.1.2)
     public_suffix (3.1.0)
-    puma (3.12.1)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -298,7 +299,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mini_magick (= 4.7.0)
   pg
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   rails-controller-testing
   rails-i18n