diff --git a/Backend/Hotel/Gemfile b/Backend/Hotel/Gemfile
index 99b4769..d1a40c3 100644
--- a/Backend/Hotel/Gemfile
+++ b/Backend/Hotel/Gemfile
@@ -6,7 +6,7 @@ gem 'rails', '~> 5.0.0', '>= 5.0.0.1'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Backend/Hotel/Gemfile.lock b/Backend/Hotel/Gemfile.lock
index 3ea8558..5118c49 100644
--- a/Backend/Hotel/Gemfile.lock
+++ b/Backend/Hotel/Gemfile.lock
@@ -86,7 +86,8 @@ GEM
     nio4r (2.5.2)
     nokogiri (1.10.4)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.1)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -187,7 +188,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   jquery-rails
   listen (~> 3.0.5)
-  puma (~> 3.0)
+  puma (~> 4.3)
   rails (~> 5.0.0, >= 5.0.0.1)
   rspec-rails
   sass-rails (~> 5.0)