A bit later than expected, but charged with new awesome features and stability, CakePHP 2.2.0-RC2 finally lands for a final test-drive before it's marked stable. As mentioned in previous releases, 2.2.x will be an API compatible release with 2.0.x, and 2.1.x and should be generally transparent when upgrading, except for a few additions you need to make in configuration files.
We let a few new features sneak into this release as we considered them safe and useful enough to our community. A quick list of new features added in 2.2.0-RC2:
A few new methods were added to the Validation class:
mimeType. Natural number validation is used in case you want a numeric validation but only for non-negative numbers. Upload related methods were added to make it easier for models to correctly validate uploaded files, specifically
mimeType method will validate the correct mimetype for files without relying on file extension.
Several small enhancements were added to improve experience of baking test cases and new plugins. For instance, creating a new plugin will automatically configure it in bootstrap.php
DELETE methods' payload data will now be placed into
$request->data if it is encoded correctly. This makes it easier for controllers to implement actions transparently without taking explicit actions for each of those methods.
session.gc_maxlifetimeis now set when using files for sessions. This prevents session files from being garbage collected too early.
cake i18n extractnow has an
--overwriteoption to force overwriting all existing pot files.
- App::uses() now supports namespaced classes better.
- belongsTo and hasOne associations should generate fewer queries when recursive > 1.
- TranslateBehavior::unbindTranslation() works as documented now.
- HtmlHelper::tableHeaders() now accepts HTML attributes for each cell.
- Router::setExtensions() was added to allow new extensions to be added instead of replacing all existing extensions.
- Security::rijndael() was added and exposed to CookieComponent. This allows strong encryption to be used, and is recommended for all applications using ciphered cookies.
- The datasource method cache is now more resistant to collisions.
- Email templates using images now work correctly more often.
- app/Console/cake now correctly determines the app directory in more situations.
- PUT and DELETE requests with
application/www-form-urlencodeddata are now automatically parsed and set as
$this->datain the request object.
- Session cookies are now httpOnly by default.
- All validation errors are returned when saving/validating associated models if the primary model's validation fails.
View the complete changelog available . Download a packaged release 
As always, thanks to the friendly CakePHP community for the patches, documentation changes and new tickets. Without you there would be no CakePHP!