Roon OS 2.1 - UEFI build only?

[Wade_Oram]

From the Roon OS 2.1 release announcement:

@vova

Yes, this is version 2.1. You might be wondering what happened to 2.0. During the transition to Harman, version 2.0 should have been the UEFI build, but it wasn’t. We’re correcting that now with this update. If you want to think of a 2.0 version, consider builds 1.0.256 to 1.0.261 as 2.0 (builds 256-261).

This implies that the UEFI boot was introduced in build 256. As a consequence, it is probable that if your Nucleus/ROCK/MOCK device reports a Roon OS build number lower than 256, then it is using BIOS boot. If it reports a Roon OS build number equal to or greater than 256, then it is using UEFI boot.