Bundler could not find compatible versions for gem “railties” for Rails 4.0.0

Question

I am trying to upgrade to Rails 4.0.0, and I changed the gem versions of sass-rails and coffee-rails. I need to resolve this gem conflict between <

Answer 1

You have an outdated version of Devise, use Rails 4 compatible

gem 'devise', '~> 3.0.0.rc'

Also change coffee-rails to

gem 'coffee-rails', '~> 4.0.0'

and try doing

bundle update coffee-rails