We still don't know all that much about X-Men: Apocalypse apart from that we will be able to see it from May 27, 2016. Singer is supposed to have suggested that we should only expect to see the younger cast in X-Men: Apocalypse; though regardless of this, a couple of the older X-Men cast members are still hoping to make an appearance.
This is what Ian McKellen and Patrick Stewart had to say in a BuzzFeed Brews video interview, (via ComicBook.com) when asked whether they will feature in part of X-Men: Apocalypse.
Sir Patrick Stewart:
How can anything be apocalyptic without Magneto and Xavier? It doesn’t make sense.
Sir Ian McKellen:
I don’t see how they can do it without us, really. Do you? I think if enough people start sending messages to Bryan Singer and Lauren Shuler Donner, then yeah... I would even wear the helmet. I really would.
Here is the full BuzzFeed interview with the two stars:
Would you like to see the two veterans feature in the upcoming X-Men: Apocalypse?