I see documentation of 1.0 (i.e
https://archive.org/details/sysv-dwb/page/n5/mode/2up)
I see a copy of 2.0 for 3B2 (i.e.
https://archives.loomcom.com/3b2/software/Documenters_Workbench/)
From there things get a little less clear, it seems like we jump to
3.2 with SysVR3.2?
The jump might be due to the effect that for quite a while outside
AT&T it was marketed by SoftQuad (Toronto). (See also
<https://en.wikipedia.org/wiki/SoftQuad_Software>).
jaap