diff --git a/lib/asset_sync/config.rb b/lib/asset_sync/config.rb
index 2ea3a51e..88d88510 100644
--- a/lib/asset_sync/config.rb
+++ b/lib/asset_sync/config.rb
@@ -110,7 +110,7 @@ def google?
     end
 
     def yml_exists?
-      defined?(Rails.root) ? File.exists?(self.yml_path) : false
+      defined?(Rails.root) ? File.exist?(self.yml_path) : false
     end
 
     def yml
diff --git a/lib/asset_sync/engine.rb b/lib/asset_sync/engine.rb
index 4e7fd887..0f6aa534 100644
--- a/lib/asset_sync/engine.rb
+++ b/lib/asset_sync/engine.rb
@@ -7,10 +7,10 @@ class Engine < Rails::Engine
       app_initializer = Rails.root.join('config', 'initializers', 'asset_sync.rb').to_s
       app_yaml = Rails.root.join('config', 'asset_sync.yml').to_s
 
-      if File.exists?( app_initializer )
+      if File.exist?( app_initializer )
         AssetSync.log "AssetSync: using #{app_initializer}"
         load app_initializer
-      elsif !File.exists?( app_initializer ) && !File.exists?( app_yaml )
+      elsif !File.exist?( app_initializer ) && !File.exist?( app_yaml )
         AssetSync.log "AssetSync: using default configuration from built-in initializer"
         AssetSync.configure do |config|
           config.fog_provider = ENV['FOG_PROVIDER'] if ENV.has_key?('FOG_PROVIDER')
@@ -44,7 +44,7 @@ class Engine < Rails::Engine
 
       end
 
-      if File.exists?( app_yaml )
+      if File.exist?( app_yaml )
         AssetSync.log "AssetSync: YAML file found #{app_yaml} settings will be merged into the configuration"
       end
     end
diff --git a/lib/asset_sync/storage.rb b/lib/asset_sync/storage.rb
index 822b11a7..3e369d4f 100644
--- a/lib/asset_sync/storage.rb
+++ b/lib/asset_sync/storage.rb
@@ -73,7 +73,7 @@ def get_local_files
           log "Using: Rails 4.0 manifest access"
           manifest = Sprockets::Manifest.new(ActionView::Base.assets_manifest.environment, ActionView::Base.assets_manifest.dir)
           return manifest.assets.values.map { |f| File.join(self.config.assets_prefix, f) }
-        elsif File.exists?(self.config.manifest_path)
+        elsif File.exist?(self.config.manifest_path)
           log "Using: Manifest #{self.config.manifest_path}"
           yml = YAML.load(IO.read(self.config.manifest_path))
    
@@ -150,8 +150,8 @@ def upload_file(f)
         log "Overwriting #{f} with custom headers #{files_with_custom_headers[f].to_s}"
       elsif key = self.config.custom_headers.keys.detect {|k| f.match(Regexp.new(k))}
         headers = {}
-        self.config.custom_headers[key].each do |key, value|
-          headers[key.to_sym] = value
+        self.config.custom_headers[key].each do |k, value|
+          headers[k.to_sym] = value
         end
         file.merge! headers
         log "Overwriting matching file #{f} with custom headers #{headers.to_s}"
@@ -166,7 +166,7 @@ def upload_file(f)
         # as we will overwrite file.css with file.css.gz if it exists.
         log "Ignoring: #{f}"
         ignore = true
-      elsif config.gzip? && File.exists?(gzipped)
+      elsif config.gzip? && File.exist?(gzipped)
         original_size = File.size("#{path}/#{f}")
         gzipped_size = File.size(gzipped)
 
diff --git a/spec/dummy_app/Rakefile b/spec/dummy_app/Rakefile
index 55568624..8d768cfc 100644
--- a/spec/dummy_app/Rakefile
+++ b/spec/dummy_app/Rakefile
@@ -3,7 +3,7 @@ require 'rubygems'
 ENV['RAILS_ROOT'] = File.dirname(__FILE__)
 # Set up gems listed in the Gemfile.
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
-require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
+require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
 # require 'rails/all'
 require "action_controller/railtie"
 require "sprockets/railtie"