diff --git a/alpha-blog/Gemfile b/alpha-blog/Gemfile
index 4eef436..2d0560d 100644
--- a/alpha-blog/Gemfile
+++ b/alpha-blog/Gemfile
@@ -9,7 +9,7 @@ end
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.1.7'
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/alpha-blog/Gemfile.lock b/alpha-blog/Gemfile.lock
index 94ef32f..b2220e9 100644
--- a/alpha-blog/Gemfile.lock
+++ b/alpha-blog/Gemfile.lock
@@ -92,7 +92,8 @@ GEM
     pg (0.21.0)
     pg (0.21.0-x86-mingw32)
     public_suffix (4.0.1)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -183,7 +184,7 @@ DEPENDENCIES
   coffee-rails (~> 4.2)
   jbuilder (~> 2.5)
   pg
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.1.7)
   sass-rails (~> 5.0)
   selenium-webdriver