For the backers who choosed GOG and not received the Imperial Edition, TET posted some hours ago in the topic of the game release in GOG:

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Anyone who backed the Original Sin Kickstarter and claimed his or her copy of Divinity: Dragon Commander on GOG and *didn't* get the Imperial Edition code issued, please contact Support and we will give you a free code for the DLC. In the subject of your ticket, please put, "Imperial Edition Upgrade for Kickstarter Backer".

Sorry that took so long.

As a further note: anyone who does not have Dragon Commander in the language that he or she expected upon purchase, please sit tight. Larian is building us the foreign language versions as fast as they can, and once we have a given language, we will upload it to our CDN at super lightning speeds*.

*due to recent OSHA legislation, our server gnomes are now no longer legally allowed to use actual lightning during uploads, but they will go as fast as they can.