Disable cache digest in rails4

Question

Im upgrading from rails 3.2.13 to rails 4.0.1. I'm facing problem with caching which giving me undefined method 'expired_fragment'.

Is there a way to disable cache digest?

I added these gems as well:

gem 'actionpack-page_caching', github: 'rails/actionpack-page_caching'
gem 'actionpack-action_caching', github: 'rails/actionpack-action_caching'
gem 'rails-observers', github: 'rails/rails-observers'

but it seems like the caching is not performing like last time.

Any guidance, or is someone else facing the same problems?

source 'http://rubygems.org'

gem 'activerecord-session_store', '0.1.0'
gem 'actionpack-page_caching', github: 'rails/actionpack-page_caching'
gem 'actionpack-action_caching', github: 'rails/actionpack-action_caching'
gem 'builder', '3.1.0'
gem 'carrierwave', '0.9.0'
gem 'dalli', '2.6.4'
gem 'mysql2', '0.3.14'
gem 'protected_attributes', '1.0.5'
gem 'rails', '4.0.1'
gem 'rails-observers', github: 'rails/rails-observers'
gem 'RubyInline', '3.12.2'
gem 'sass-rails', '4.0.1'
gem 'therubyracer', '0.12.0'
gem 'thin', '1.6.1'
gem 'unf', '0.1.3'
gem 'uglifier', '2.3.2'