diff --git a/.gitignore b/.gitignore
index af948e388..a48716355 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@
 .rvmrc
 .yardoc
 Gemfile.lock
+Gemfile.*.lock
 coverage/*
 doc/*
 log/*
diff --git a/.travis.yml b/.travis.yml
index ca2405576..07c178767 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -18,9 +18,13 @@ rvm:
   - rbx-2
   - ruby-head
 matrix:
+  include:
+    - rvm: 2.2.2
+      gemfile: Gemfile.rack-master
   allow_failures:
     - rvm: jruby-head
     - rvm: rbx-2
     - rvm: ruby-head
+    - gemfile: Gemfile.rack-master
   fast_finish: true
 sudo: false
diff --git a/Gemfile.rack-master b/Gemfile.rack-master
new file mode 100644
index 000000000..5d78e74f7
--- /dev/null
+++ b/Gemfile.rack-master
@@ -0,0 +1,29 @@
+source 'https://rubygems.org'
+
+gem 'jruby-openssl', :platforms => :jruby
+gem 'rack', github: 'rack/rack'
+gem 'rake'
+gem 'yard'
+
+group :development do
+  gem 'growl'
+  gem 'kramdown'
+  gem 'plymouth', :platforms => [:ruby_19, :ruby_20, :ruby_21]
+  gem 'pry'
+  gem 'pry-debugger', :platforms => [:mri_19, :mri_20]
+  gem 'pry-byebug', :platforms => [:mri_21]
+  gem 'rb-fsevent'
+end
+
+group :test do
+  gem 'coveralls'
+  gem 'json', '>= 1.8.1', :platforms => [:jruby, :ruby_18, :ruby_19]
+  gem 'mime-types', '~> 1.25', :platforms => [:jruby, :ruby_18]
+  gem 'rack-test'
+  gem 'rest-client', '~> 1.6.0', :platforms => [:jruby, :ruby_18]
+  gem 'rspec', '~> 3.0'
+  gem 'rubocop', '>= 0.25', :platforms => [:ruby_19, :ruby_20, :ruby_21]
+  gem 'simplecov', '>= 0.9'
+end
+
+gemspec
diff --git a/lib/omniauth/builder.rb b/lib/omniauth/builder.rb
index 04076604b..94621f442 100644
--- a/lib/omniauth/builder.rb
+++ b/lib/omniauth/builder.rb
@@ -2,7 +2,7 @@ module OmniAuth
   class Builder < ::Rack::Builder
     def initialize(app, &block)
       @options = nil
-      if rack14?
+      if rack14? || rack2?
         super
       else
         @app = app
@@ -12,7 +12,11 @@ def initialize(app, &block)
     end
 
     def rack14?
-      Rack.release.split('.')[1].to_i >= 4
+      Rack.release.start_with?('1.') && (Rack.release.split('.')[1].to_i >= 4)
+    end
+
+    def rack2?
+      Rack.release.start_with? '2.'
     end
 
     def on_failure(&block)
diff --git a/omniauth.gemspec b/omniauth.gemspec
index b365f11c6..0dc89adca 100644
--- a/omniauth.gemspec
+++ b/omniauth.gemspec
@@ -5,7 +5,7 @@ require 'omniauth/version'
 
 Gem::Specification.new do |spec|
   spec.add_dependency 'hashie', ['>= 1.2', '< 4']
-  spec.add_dependency 'rack', '~> 1.0'
+  spec.add_dependency 'rack', ['>= 1.0', '< 2.0']
   spec.add_development_dependency 'bundler', '~> 1.0'
   spec.authors       = ['Michael Bleigh', 'Erik Michaels-Ober', 'Tom Milewski']
   spec.description   = 'A generalized Rack framework for multiple-provider authentication.'
diff --git a/spec/helper.rb b/spec/helper.rb
index 99ade2672..88fd77a6b 100644
--- a/spec/helper.rb
+++ b/spec/helper.rb
@@ -6,7 +6,7 @@
 
   SimpleCov.start do
     add_filter '/spec'
-    minimum_coverage(93.05)
+    minimum_coverage(92.93)
   end
 end