LE 9.2.8 exists for Slice3 users with some changes that were needed for widevine support. If you don't use Netflix/Amazon or similar there's no need to update. There are no dedicated Slice3 images for LE10/LE11 but you should be able to cross-grade to RPi2 .. although we have not formally made an RPi2 image yet (maybe soon, for 10.0.2). LE10/LE11 images will be missing support for 3D and software optimised HEVC playback so if you need either of those it'll be best to remain on LE 9.2.x. Anyone with an original CM(1) board will want to remain on the legacy images as those run better on the older/lower spec.
NB: I shipped my Slice3 box to HiassofT last year. I'm not expecting him to do much/anything with it, but at least our primary RPi image maintainer has a sample box. If someone reports breakage at least he'll be able to test it.