As I understand it the rule hasn't changed
The DLRA rule said limited perforations in the armpit and the back of the knee
There was a clarification from the SCTA that reads Emphasize 7.C.2 (p. 110):
Underline “No cloth or non-leather panels are allowed.”
Reason: People still show up with illegal leathers.
This was due to a couple of incidents, in particular when a guy stepped off his bike at 145 ish mph because it was on fire and he got too hot
and another where a guy burned himself when his blow off valve, which was poorly placed, blew off. this also prompted a separate rule change
1.Affix a patch over the perforations and stretch panels
2.wear fire proof underwear under your leathers
3. go to the back of the rule book and find the page marked rule change
And where it says "One-piece or two-piece 350 deg. (zipped together) all leather is required"
means the metal zip, must be stitched to the leather,
not the lining
So, David, what we learned from the investigation was that fire is just as hot in in Aus as it is in the USA
And from what I observed at Bonneville, nobody was wearing leathers that were designed 50 years ago