Read up in the leaks. There have been several, without a date but still:
This is one of the styles most likely
This is the veteran style
/
And this could be the T3 gifted tank.
It's coming. Just not sure when. The current is running out of Nov 30th so it will be after that. When it's in December then that might be a reason it's not in the calendar but it wasn't the last years either
Source: https://www.reddit.com/r/WorldofTanks/comments/yu3mtj/to_everyone_asking_for_well_deservered_reward/