Suedkiez
(Just a fellow user like you)
3
Most likely your ROCK was installed in Legacy BIOS mode, before RoonOS supported UEFI mode.
In this case, the RoonOS 1.0 (build 259) is the latest available OS version and you are up to date in this respect.
Tailscale was made available in RoonOS 2.1. However, OS 2.x requires that ROCK is installed in UEFI mode:
The only way to change this is by reinstalling ROCK from scratch, after switching from Legacy BIOS to UEFI in the NUC’s BIOS settings.