The 2017 Sporting and Technical regulations have been published on the FIA site.
A few things that jumped out at me:
From 2018 drivers will be limited to only 3 ICEs, Turbos and MGUHs, and 2 Batteries, MGUKs and Control Electronics per season!
They have implemented a long winded and formula driven aproach to ensure a supply of engines that, had it been in effect last year, would have forced Honda to supply Red Bull and Toro Rosso. Or, due to Renault only supplying 1 team, forced Honda to supply one of them and Renault to supply the other.