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.