diff --git a/spec/tester_ar/Gemfile b/spec/tester_ar/Gemfile
index 68bf1615..cd0bb32b 100644
--- a/spec/tester_ar/Gemfile
+++ b/spec/tester_ar/Gemfile
@@ -2,7 +2,7 @@
 
 source 'https://rubygems.org'
 
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 gem 'rails', '~> 5.1.6'
 gem 'sqlite3'
 
diff --git a/spec/tester_ar/Gemfile.lock b/spec/tester_ar/Gemfile.lock
index f2228001..91f927f7 100644
--- a/spec/tester_ar/Gemfile.lock
+++ b/spec/tester_ar/Gemfile.lock
@@ -76,7 +76,8 @@ GEM
     nio4r (2.4.0)
     nokogiri (1.10.4)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.1)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -134,7 +135,7 @@ DEPENDENCIES
   graphql
   listen (>= 3.0.5, < 3.2)
   nokogiri (>= 1.10.4)
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.6)
   sqlite3