diff --git a/Gemfile b/Gemfile
index 2f350d0..5f88206 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,7 @@ gem "rails", "~> 5.0.7", ">= 5.0.7.2"
 gem "pg"
 
 # Use Puma as the app server
-gem "puma", "~> 3.0"
+gem "puma", "~> 4.3"
 
 # Rack Middleware for handling Cross-Origin Resource Sharing (CORS), which makes cross-origin AJAX possible
 gem "rack-cors"
diff --git a/Gemfile.lock b/Gemfile.lock
index 554365d..b648da0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -107,7 +107,8 @@ GEM
     pg (1.1.4)
     psych (3.1.0)
     public_suffix (4.0.5)
-    puma (3.12.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-cors (1.1.0)
       rack (>= 2.0.0)
@@ -226,7 +227,7 @@ DEPENDENCIES
   database_cleaner
   listen (~> 3.0.5)
   pg
-  puma (~> 3.0)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.0.7, >= 5.0.7.2)
   rails_best_practices