diff --git a/spec/jsonapi_app/Gemfile b/spec/jsonapi_app/Gemfile
index f2baa44..0781c93 100644
--- a/spec/jsonapi_app/Gemfile
+++ b/spec/jsonapi_app/Gemfile
@@ -13,7 +13,7 @@ gem 'rails', '~> 5.0.1'
 gem 'pg'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+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/spec/jsonapi_app/Gemfile.lock b/spec/jsonapi_app/Gemfile.lock
index fdcf778..247b744 100644
--- a/spec/jsonapi_app/Gemfile.lock
+++ b/spec/jsonapi_app/Gemfile.lock
@@ -70,7 +70,8 @@ GEM
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     pg (0.21.0)
-    puma (3.12.2)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -124,7 +125,7 @@ DEPENDENCIES
   jsonapi-resources
   listen (~> 3.0.5)
   pg
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.0.1)
 
 BUNDLED WITH