Rails 2.2 won't be all about new features. The Rails team is also taking advantage of this release to deprecate some existing features. Here's a list of what will be going away in the 2.2 release:

  • The country_select helper has been removed. This is the one most likely to affect existing applications, I think, but it's going away because of arguments over which list of countries to use. The deprecation page points to a couple of replacement plugins.

  • Rails::SecretKeyGenerator has been replaced by ActiveSupport::SecureRandom.
    render_component is deprecated. If you need it, grab the render_components plugin.

  • ActiveRecord::Base.allow_concurrency no longer has any effect. Might as well stop calling it. Remember, though, that ActiveRecord is getting connection pool management.

  • ActiveRecord::Errors.default_error_messages has been deprecated in favor of I18n.translate('activerecord.errors.messages')

  • The %s and %d interpolation syntax for internationalization is deprecated.

  • String#chars has been deprecated in favor of String#mb_chars.

  • Durations of fractional months or fractional years are deprecated. Use Ruby's core +Date+ and +Time+ class arithmetic instead.