Originally Posted by Koru Flyer

My understanding and experience is that. Prior to some stage I think it was around 2019 for Avios and GUF upgrades via BA you needed the underlying award class (Z for first, I forget the rest ;-) ) to be available. If it was not available you then needed (T, I, A) to be available to then use the Joker to open up award space (I think also you can Joker /D/ as well?). Curiously at that time, if it was a TA booking you only needed /I/ and /A/ to be available to upgrade with a GUF so you could getter better availability through a TA.

Then around 2019, they levelled it all up so you needed either Avios /Z/ or First revenue /A/ to GUF from Club to First, and the Joker in the use of a GUF became irrelevant for First upgrades.
- So booking an award ticket with Avios only, you need either award availability to use a Joker the right revenue fare bucket - and they must not have run out of the Joker stock for that flight
- Booking an upgrade with a GUF either cash or Avios you can have either /Z/ or /A/ available. So the Joker is irrelevant in that situation. In my experience /A/ is usually what they take. Which incidentally gives you a very flexible ticket, as to make a change you just need /A/ to be available.

That said I believe that you can Joker /D/ class as well, so that if you GUF from WTP you might be able to use a Joker to facilitate that upgrade if no /I/ is available.

I have had the odd agent, when there has been no /A/ available go on hold, saying lets look at a "space release" (what BA now calls Jokers) and then come back with that there is nothing they can do, not surprising. As another hint, I have noticed large changes in POS availability in /A/ class. So make sure the BA agent is logged into the POS with the availability you need.

KF