As of SDX 4.45 Indus.sys contains three versions of synchromesh code (all 68kbps): INDUS GT 1.1, INDUS GT 1.2 (most common), CA-2001 (with support from sup8pdct). Track buffering is not yet implemented, but it will surely be in one of the next releases
68k (SuperSynchromesh and indus.sys), but indus.sys is not enabling track buffering with Ramcharger now.
New indus.sys probably enables only 68k on CA2001 what was not working before (instead of using 38k synchromesh or ca2001.sys (written by Draco (I am not 100% sure) in early 1990's - I have diskette from Atari Magazyn with it), which I think contains the same Z80 code.
If I understand correctly, indus.sys never supported track buffering, only super synchromesh did it.
But maybe trub will write more.