OK, first, I use one of the google free Huawei phones with no GMS services, install the app using a google play compatible client Aurora Store (auroraoss.com)
Used the MicroG services (https://microg.org) which is an opensource implementation of the google GMS services to at least to get the notifications working within the app and other GMS dependent apps.
The last or recent update to Dozen, the app no longer works with the MicroG services, the application will show the logo and disappear (Or Crash). Understand, you won’t support the MicroG services and that is respected, however, some of these open-source phones such as fair phone use the microg services by default for privacy reasons.
As a workaround to get Dozen working on the Huawei phone, used Gspace, which is an island that runs the google services but without the notifications.
Unlikely your development team will want to look into it, but if they do I can work with them or provide any required logs or access.
So in brief:
- Without GMS services, the app runs but without notifications
- With GMS services, application runs without issues
- With MicroG services, the application no longer opens.