diff --git a/Gemfile b/Gemfile
index 24fbed33..0ef1d540 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ gem "rdoc"
 gem "rake-compiler"
 
 gem "nio4r", "~> 2.0"
-gem "rack", "< 3.0"
+gem "rack", "~> 1.6"
 gem "minitest", "~> 5.11"
 gem "minitest-retry"
 gem "minitest-proveit"
diff --git a/lib/puma/binder.rb b/lib/puma/binder.rb
index 1b9517b9..7759c85b 100644
--- a/lib/puma/binder.rb
+++ b/lib/puma/binder.rb
@@ -11,7 +11,7 @@ module Puma
   class Binder
     include Puma::Const
 
-    RACK_VERSION = [1,3].freeze
+    RACK_VERSION = [1,6].freeze
 
     def initialize(events)
       @events = events