As your question is specific for one app and there is a App Thread / developer on the Community please continue in that thread and this one is closed.
(To answer the first question, there are > 580 Apps in the Athom App store, most are stable. It depends over time (other things breaking an App, Homey Firmware or a Vendor API changing or a Local device Firmware) Please search the Forum specific for what you need. You refer to an un-published App on a Developer-Repository.)