The apk was signed with a generated key which changes every time the apk is generated. This means, that android might refuse to install it if another apk with the same app was installed previously. You'll have to deinstall it. Doing so will delete all settings and cache.

In order to prevent that, you have to generate your own key or use our public key:

To generate your own key:
- https://stackoverflow.com/questions/3997748/how-can-i-create-a-keystore. Use 'alpinemaps' as the alias!
- If you have the android dev setup ready in Qt Creator, you can also create the keystore via Projects (on the left side toolboar) -> Android Qt ... -> Build -> Build Steps -> Build Android APK -> Application Signature -> Create.  Use 'alpinemaps' as the alias!
- Then you have to encode the keystore in base64, e.g., on linux via 'base64 keystorefile > keystorefile.base64'
- Finally, create the following secrets in github -> your repo -> Settings -> Secrets and variables -> Actions -> Repository secrets
  SIGNINGKEYBASE64 = the base64 encoded key
  KEYSTOREPASSWORD = the password used to create the keystore

To use our public key, go to https://github.com/AlpineMapsOrg/renderer/blob/main/creating_apk_keys.md

Oh, and I hope this saved your day :)