They are still on the app store, but unlike the keyboard app itself don’t seem to be updated for modern Android devices. For example:
I’ve sent Exideas a support email asking why this is the case, so I guess when and whether they respond will be something of a litmus test of how active their support is these days. In the meantime, it seems the language modules/dictionaries can be downloaded as APKs directly from their website. They should not at all be necessary to use the keyboard, in any case.
Glad to hear it and I hope Exideas’ admittedly questionable support won’t be a big issue going forward for you. It hasn’t really been for me - the app is pretty solid. It saddens me that novel designs like this never seem to catch on, between public inertia and established corporate actors actively trying to suppress anything new.