Recently got a call from my dealer who said there was a transmission "software update" for my MY18 SVR. A quick check on Topix and I can see: H136 - Pass by Noise in Latched Special Programs Modes

Which sounds like someone has decided the car is too noisy and won't pass UN-ECE R51.02 .The description of the fix only mentions the pass-by noise regulation and that it's going to default to standard mode on each startup - at the moment it'll stay in "Dynamic" (unless it's been sitting overnight). Hopefully it doesn't affect the exhaust note - remember everyone complaining about their V6s not sounding the same after the O2 sensor update.

Has anyone had the fix applied - any noticeable change in the sound?

 

Yep. No noticable effect on the sound in my V8 AWD but the only effect I'm aware of is the one you've noted - that the car used to remember Dymanic mode (if selected) for up to 6 hours, as documented in the manual, but now it always resets to DM off on each startup. Annoying but doesn't really affect me, although I do think it's a bit bad for Jaguar to break a documented behaviour of the car.