Dan – that is absolutely NOT true. We notified users that an update was available. But each individual user had to manually do the update themselves.
Acrobat DC was announced all over the web, but our release was here - http://www.adobe.com/news-room/pressreleases/201503/031715AdobeIntroducesDocumentCloud.htm l
All registered plugin developers are part of our pre-release program. I don’t know why you and your organization are not part of that, but if you contact me offline I’ll see about getting you added for the future.
All of the Carbon-related APIs have been removed as part of the Acrobat DC SDK, for the reasons you note. We have provided alternative APIs where possible, such as new rendering APIs that can now be used from BOTH the PDFL and the plugin models.