diff --git a/Gemfile b/Gemfile
index c6f150b..775c7a3 100644
--- a/Gemfile
+++ b/Gemfile
@@ -20,7 +20,7 @@ gem "bootstrap_form", "~> 4.0"
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.2.2'
 # 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/Gemfile.lock b/Gemfile.lock
index f0cf9f6..6986678 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -149,7 +149,8 @@ GEM
       pg
     psych (3.1.0)
     public_suffix (4.0.3)
-    puma (3.12.4)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -297,7 +298,7 @@ DEPENDENCIES
   pg (~> 1.1, >= 1.1.4)
   pg_search (~> 2.1, >= 2.1.7)
   postgresql (~> 1.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.2)
   roo (~> 2.8.0)
   roo-xls (~> 1.1)