I'm still using the keyboard despite the expired beta because it works great, but without the proper theme I do a lot more typing errors because the keys are smaller. Annoying, but I didn't find a better alternative yet.
: Don't do like Kii did: abandon the software and, while the apk is still out there, the pro features will never be accessible by anyone again because of artificial limitations. If you abandon it, please push one last unlocked apk! Otherwise your work just goes to waste and people won't benefit from it, which is the point of developing things isn't it?