The New Bloom update usually ties in with Chinese New Year, which is later this month. Last year the update brought with it the Year Beast challenge game mode where teams would try and inflict as much damage to the Year Beast as possible in order to gain rewards. It appears that this will return with the new update.
The teaser also hinted that Winter Wyvern will be added to the game as the newest playable hero in this update.
With Reddit being Reddit they have analysed the trailer extensively and seem to think the Crystal Maiden will finally get a move speed buff as she can be seen running in the trailer.
The trailer is available below.