Keyman 12.0 introduced a new feature for Predictive Text services that can be used with keyboards.
Unfortunately, it’s currently incompatible with some older devices (Android 4.4 to Android 6.0) and prevents a Keyman keyboard from loading.
@joshua_horton started working on a fix but we don’t have an estimate when that will be ready.
Sorry for the inconvenience, but can you roll back to Keyman 11.0.2107 for now?
Thanks to @joshua_horton 's persistence, Keyman 12.0.4215 should work for your device!
I was able to use the predictive text on the default sil_eurolatin keyboard it in an emulator.
Please download the Keyman update and see if it works for you.