A Prediction of some Clash of Clans fanatics that December update will feature a new level Air defenses, sweepers and walls. It has been quite a while since they received an upgrade.
These have also ignited rumors that the Air units will also receive their own upgrades in order to balance the gameplay in "Clash of Clans." According to iDigital Times, one avid "Clash of Clans" data miner was able to find a shipwreck sprite hidden in the game. These lead to various speculations that mobile game developer Supercell is planning to a sea battle feature in the game.
There also rumors that sea monsters and mermaids will be included as well. Unfortunately, these are all just speculations as of the moment and there are no proofs yet to back it up.
Another rumored feature reported from HNGN, is the goblin versus wizard battle but there not quite a ton of information about it as of the moment. There are evidences however, that Supercell is planning something for the Red Day event. A number of CoC units and structures were found bearing red color and markings.
Players will be able to repair shipwrecks when the update is set and ready. Repairing shipwrecks means rewarding players with a lot more coins and gems in their account. This new feature is not yet confirmed by Supercell. But if they do add this feature, the game is going to become more interesting.
According to an article from Jobs & Hire, Since Supercell only confirmed the upcoming December 2016 update, the new features to be introduced are still mere speculations up to this point. Also, Supercell has yet to confirm the official release date for "Clash of Clans" December 2016 update, reports though predicted that the update will likely occur on December 1.