Though there's nothing listed yet, despite the very first Surface Pro 2 firmware and driver pack releasing, the Update History pages for the Surface 2 line of devices have shown up on the Microsoft Surface web site.
The pages generally provide a good timeline of fixes provided by Microsoft for their hybrid computing devices, and allow IT Pros to stay apprised of updates that may help solve end-user complaints. It's a good idea to keep these pages bookmarked.
Here's the locations…
Surface 2 (RT): Surface 2 update history
Surface Pro 2: Surface Pro 2 update history
And, of course, the original Surface pages are still intact…
Surface RT: Surface RT update history
Surface Pro: Surface Pro update history