diff --git a/Gemfile b/Gemfile
index f9494a4..762ed86 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.0'
 # Use PostgreSQL as the database for Active Record.
 gem 'pg'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production
diff --git a/Gemfile.lock b/Gemfile.lock
index b74d7b7..48ce3c7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -73,7 +73,8 @@ GEM
     nokogiri (1.8.1)
       mini_portile2 (~> 2.3.0)
     pg (0.20.0)
-    puma (3.8.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.2)
     rack-cors (0.4.1)
     rack-test (0.6.3)
@@ -139,7 +140,7 @@ DEPENDENCIES
   jwt
   listen (>= 3.0.5, < 3.2)
   pg
-  puma (~> 3.7)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.1.0)
   simple_command