diff --git a/Gemfile b/Gemfile
index 69b9cd0..41ef586 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ ruby "2.6.3"
 gem 'rails', '~> 5.1.6'
 
 # A Ruby/Rack web server built for concurrency
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index f6f9538..32a5de3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -163,7 +163,8 @@ GEM
       mini_portile2 (~> 2.4.0)
     orm_adapter (0.5.0)
     popper_js (1.14.5)
-    puma (3.12.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
     rack (2.0.8)
@@ -304,7 +305,7 @@ DEPENDENCIES
   mongoid-history (= 0.8.1)
   mongoid-rspec (= 4.0.1)
   nokogiri (~> 1.10.8)
-  puma (~> 3.12)
+  puma (~> 4.3)
   pundit (= 1.1.0)
   rails (~> 5.1.6)
   rspec-rails (= 3.7.2)