A new Asterix is due out in French in October 2017, so the English edition should be soon afterwards.
The
Asterix blog includes a page-trailer: Obelix is working on a menhir when a little boy remarks that it must be great making menhirs, but then says that when he grows up he wants to be a warrior like Asterix: smart and quick-witted and going on loads of missions. Obelix is disheartened and throws the menhir away. (It's not clear if the little cheek ends up under the menhir! :)
When Asterix asks why he threw the menhir, Obelix announces that he is giving them up. He will now be Obelix, the smart and quick-witted warrior. He gets himself a helmet like Asterix's and a little sword.
The question now is if the next album will be an adventure of Obelix the Gaul? All that the authors reveal is that it will be another story of the heroes travelling abroad.