An early look at our Patch Notes are available on our forums. Unfortunately, the notes are too large to fit onto steam in this format, an official patch notes post will accompany the release next week.
I will also take this opportunity to point out that as is normal for large updates, saved games from earlier versions will not be compatible with No Step Back. An opt-in rollback to the current live version will be provided when No Step Back and the Barbarossa update launch