Config files need to be converted when upgrading.
When creating new sources or editing existing ones, the SAP passwords are encrypted with a key that is derived from the Windows account that is configured to run the BC service. The passwords can only be accessed from the same service account, when restoring a backup or moving the files to a different machine. If the service account changes, passwords need to be re-entered manually.
Passwords are no longer part of sources/[name]/general.json. They are stored in sources/[name]/password.json now.