It has always been a strong recommendation to read the Following -current FAQ
before upgrading to -current, or from and older -current to a new -current.
At this time, you will not be able to successfully upgrade if you do not read and follow this FAQ before taking any action.
This particular change requires
- Delete all installed packages except firmware prior to upgrading.
- Update the password database file while running the RAMDISK kernel
- Reset login records
- Reinstall all packages, built with the new ABI.
The FAQ doesn't state this, as it is considered obvious: back up your system first