The main difficulty I can see is that those devices just don’t have enough screen real estate; Versu needs you to be able to keep track of a good chunk of scrollback text, a half-dozen character icons at high enough resolution to see their expressions, a choice menu that doesn’t interfere too much with the other information, and so on. My guess is that making it work would be straightforward, but doing it with a non-annoying UI would be difficult.
(Emily is not, regrettably, the one who gets to make the call about which platforms Versu gets published to; and for similar business-y reasons can’t promise or predict anything on that front.)