It was confirmed by Supercell (via the forums) that the update is planned for May. Of course, plans can change. For now though, players can look forward to the arrival of boats and whatever they may bring to Clash of Clans sometime this month.
Moderator LachNessMeownster did point out the update will not be this week and that it is “very likely” that we will not be getting sneak peeks for the update. Thankfully, he’s supplied us with some:
Not Town Hall 12
No level 13 walls.
Its unique from any update, and it’s huge.
There will be no new hero levels in this update.
There will be a boat that needs repairing.
There will be an achievement called “Un-Build It”.