Adobe’s official announcement https://s3.amazonaws.com/cssdk/2015-05-22_TechPartners.html
If you are a developer and want to know how to distribute your panels, you can find more information about that here: https://www.adobeexchange.com/resources/27
Adobe wants to steer users tword their cloud services. So the Add-On Marketplace is the avenue of choice. https://creative.adobe.com/addons. You can sell to the public OR you can setup a private account so you tools only go to specific users. Then your extension would get installed through creative cloud app. If that’s not an option, you can instruct users on how to install manually. IF that’s not an option, there is also a command line interface to Extension Manager that I’ve been assured will still be functional. You can find information about that here: https://helpx.adobe.com/extension-manager/using/command-line.html
If you find your CC2014 panel is not visible in CC2015, the most common problem I’ve seen is simple to resolve, you’ll want to make sure in the panel’s manifest file that you’ve set it to work with Host applications up to 16.9. If that doesn’t do the trick for you, we’d be happy to give you a diagnostic review.
Good luck and enjoy exploring the new features of Photoshop CC2015!