If you try to publish app via Powershell to onprem or Docker sandbox environment and you get error

Unsupported symbol type 393316 where the number can be whatever then it just means that the version of the app you are trying to publish is not compatible with your installed BC version.

If you download symbols from your Business Central you try to publish and try to build the app when you will get the actual error and missing types.

Hope it helps someone to uncrypt this cryptic error message.