I have been following it.
Major thing in 6.0 -> 6.1 is stop using BIOS to access ATA drives. Many of what follows is issues that surfaced as a result of that. So for example no longer relying on BIOS you have to handle all quirks that mat arise when talking to a drive using ATA commands rather than BIOS int13h calls.
And lots of it is it stopping working with screen thief, not responding to user input .. practical stuff.
Stuff like treating SMART RAW values wrong for past 20 years .. Detect TRIM to have some idea if it's working on SMR or SSD etc.. So apart from actual beef (remove dependency on BIOS for disk IO) lot's of house hold stuff ..
As for heading: Idea is to move to RTOS32 for version 7 (https://www.real-time-systems.com/on-time-rtos-32/) for which he bought license + source code. He will be 'porting' SR to that, although I don't see how this can be anything else that a rewrite from scratch.