The Uploader plugin has upgraded major versions from 2.8 (CakePHP 1.3) to 3.0 (CakePHP 2). Since this is not a backwards compatible change, the 3.0 version can only be used in CakePHP 2.
No more UploaderComponent
During the conversion process, the primary change is that the UploaderComponent was removed and turned into a stand-alone vendor class. This was done to further encourage the use of the AttachmentBehavior. Because of this change, you will need to manually initialize the Uploader in your Controller::beforeFilter() (only if you were using the component). The property settings are now passed as an array through the constructor.
// Before
public function beforeFilter() {
$this->Uploader->tempDir = TMP;
}
// After
public function beforeFilter() {
$this->Uploader = new Uploader(array('tempDir' => TMP));
}
By instantiating the class to $this->Uploader, all of the old code should still work as normal. This change also allows the possibility to use the Uploader anywhere in the application.
No more S3TransferComponent
The S3TransferComponent was trying to do something it shouldn't have. The component was removed in favor of the Vendor/S3 class that provides far more functionality. The AttachmentBehavior has also been updated to use the S3 class instead of the component.
Certain methods are now static
The bytes(), addMimeType(), checkMimeType(), mimeType() and ext() methods are now static.
Those should be the only changes you would need to make to support the new version. There are quite a few other changes, so be sure to check out the changelog and to also check out the updated documentation.