Contract Expiration dates:
July 2018: Dinho + Toure.
Yaya will be off. Dinho might get himself a 1 year deal, however, even that isn't certain imo.
July 2019: Serge + Silva (D) + Kompany + Mangala.
Silva obviously getting a new one, which you'd expect him to sign. Kompany probably depends on injuries. You'd reasonably expect Mangala to leave and I don't really know about Serge.
July 2020: Sterling + Gundogan + Otamendi + Bravo + Delph
Firstly, I've put 2020 in there because, realistically, the club must be looking at these contracts soon, otherwise you'll end up like Arsenal.
Sterling would likely get a new deal. Gundogan depends on injuries. Otamendi may leave by then depending on new recruits. Bravo will probably be gone and you'd expect the same as delph.