Originally Posted by
anabolism
Ah, sorry, I interpreted "needed for the upgrade" as what you needed to be booked into, but you meant what you need to have available. I think it's U for PE to J, and Z for J to F, same as straight awards, but I don't know for certain.
no. i didnt put it out clearly.
for gold upgrade for 2 via TA, PE to J is booked into I class as opposed to U class because TA does not see U space.
therefore, it is interesting to do upgrade via Avios if it can be done via TA as they booked into E/I/A class as opposed to award chart which is a big deal for many people.