diff --git a/Gemfile b/Gemfile
index 4c0b2fd1..b1476845 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,6 @@ group :test do
   end
   platforms :ruby_18, :ruby_19 do
     gem "mime-types", "~> 1.25"
-    gem "json", "~> 1.8"
     gem "addressable", "~> 2.3.0"
   end
   platforms :ruby_18, :ruby_19, :ruby_20, :ruby_21 do
@@ -32,6 +31,11 @@ group :test do
     gem "rubocop", "~> 0.41.0"
     gem "test-unit"
   end
+  if RUBY_VERSION.start_with? '1.'
+    gem "json", "~> 1.8"
+  else
+    gem "json", "~> 2.0"
+  end
 end
 
 gemspec