diff --git a/gemfiles/Gemfile-rails-4-0 b/gemfiles/Gemfile-rails-4-0
index 656e84c..31c8cbd 100644
--- a/gemfiles/Gemfile-rails-4-0
+++ b/gemfiles/Gemfile-rails-4-0
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails", "~> 4.0.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-rails-4-1 b/gemfiles/Gemfile-rails-4-1
index 80938ef..07499a2 100644
--- a/gemfiles/Gemfile-rails-4-1
+++ b/gemfiles/Gemfile-rails-4-1
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails", "~> 4.1.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-rails-4-2 b/gemfiles/Gemfile-rails-4-2
index b48c5e0..d12f9a4 100644
--- a/gemfiles/Gemfile-rails-4-2
+++ b/gemfiles/Gemfile-rails-4-2
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails", "~> 4.2.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-rails-5-0 b/gemfiles/Gemfile-rails-5-0
index 6e725fb..abe80ab 100644
--- a/gemfiles/Gemfile-rails-5-0
+++ b/gemfiles/Gemfile-rails-5-0
@@ -4,3 +4,4 @@ source "https://rubygems.org"
 gemspec path: ".."
 
 gem "rails", github: 'rails/rails', branch: '5-0-stable'
+gem 'mime-types', '< 3', require: false if RUBY_VERSION.start_with?('1.9')
diff --git a/gemfiles/Gemfile-sass-3-1 b/gemfiles/Gemfile-sass-3-1
index ddb7a3f..7adb13b 100644
--- a/gemfiles/Gemfile-sass-3-1
+++ b/gemfiles/Gemfile-sass-3-1
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails"
 gem "sass", "~> 3.1.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sass-3-2 b/gemfiles/Gemfile-sass-3-2
index 34fc91b..3aaae9e 100644
--- a/gemfiles/Gemfile-sass-3-2
+++ b/gemfiles/Gemfile-sass-3-2
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails"
 gem "sass", "~> 3.2.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sass-3-3 b/gemfiles/Gemfile-sass-3-3
index 9a9401f..92f3fb6 100644
--- a/gemfiles/Gemfile-sass-3-3
+++ b/gemfiles/Gemfile-sass-3-3
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sass-3-4 b/gemfiles/Gemfile-sass-3-4
index c60265a..e564171 100644
--- a/gemfiles/Gemfile-sass-3-4
+++ b/gemfiles/Gemfile-sass-3-4
@@ -6,3 +6,4 @@ gemspec path: ".."
 gem "rails"
 gem "sass", "~> 3.4.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-2-11 b/gemfiles/Gemfile-sprockets-2-11
index 2af3c69..98e3a4c 100644
--- a/gemfiles/Gemfile-sprockets-2-11
+++ b/gemfiles/Gemfile-sprockets-2-11
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets", "~> 2.11.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-2-12 b/gemfiles/Gemfile-sprockets-2-12
index 2e2afe2..51126ae 100644
--- a/gemfiles/Gemfile-sprockets-2-12
+++ b/gemfiles/Gemfile-sprockets-2-12
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets", "~> 2.12.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-2-8 b/gemfiles/Gemfile-sprockets-2-8
index 3dbf594..2d7eb51 100644
--- a/gemfiles/Gemfile-sprockets-2-8
+++ b/gemfiles/Gemfile-sprockets-2-8
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets", "~> 2.8.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-3-0 b/gemfiles/Gemfile-sprockets-3-0
index 1954fbe..b875023 100644
--- a/gemfiles/Gemfile-sprockets-3-0
+++ b/gemfiles/Gemfile-sprockets-3-0
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets", "~> 3.0.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-4-0 b/gemfiles/Gemfile-sprockets-4-0
new file mode 100644
index 0000000..0d8841c
--- /dev/null
+++ b/gemfiles/Gemfile-sprockets-4-0
@@ -0,0 +1,9 @@
+source "https://rubygems.org"
+
+# Specify your gem"s dependencies in sass-rails.gemspec
+gemspec path: ".."
+
+gem "rails"
+gem "sprockets", "~> 4.x"
+gem 'mime-types', '< 3', require: false if RUBY_VERSION.start_with?('1.9')
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-rails-2-2 b/gemfiles/Gemfile-sprockets-rails-2-2
index 7789866..f40ba3f 100644
--- a/gemfiles/Gemfile-sprockets-rails-2-2
+++ b/gemfiles/Gemfile-sprockets-rails-2-2
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets-rails", "~> 2.2.0"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")
diff --git a/gemfiles/Gemfile-sprockets-rails-master b/gemfiles/Gemfile-sprockets-rails-master
index c4e90af..dd169bd 100644
--- a/gemfiles/Gemfile-sprockets-rails-master
+++ b/gemfiles/Gemfile-sprockets-rails-master
@@ -7,3 +7,4 @@ gem "rails"
 gem "sprockets-rails", github: "rails/sprockets-rails"
 gem "sass", "~> 3.3.0"
 gem "mime-types", "< 2"
+gem "rack", "< 2" if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2")