diff --git a/Gemfile b/Gemfile
old mode 100755
new mode 100644
index a17fa33..7c17a25
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ end
 gem 'rails', '~> 5.1.4'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 150693f..334cdea 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -108,7 +108,8 @@ GEM
     pg (0.21.0)
     popper_js (1.16.0)
     public_suffix (4.0.6)
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-test (1.1.0)
@@ -222,7 +223,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   material_icons (~> 2.2.1)
   pg (~> 0.21.0)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.4)
   rspec-rails (~> 3.7.1)
   sass-rails (~> 5.0)