I have accumulated a fair amount of Qantas frequent flyer points, which I have been using to upgrade whenever I fly to the UK.

I have accumulated a fair amount of Qantas frequent flyer points, which I have been using to upgrade whenever I fly to the UK. Can I still do so after the Qantas-Emirates alliance takes effect? I was told once that you cannot upgrade when the flight is operated by a carrier that is not Qantas (not "Qantas-metal") even though the flight has a QF number and the ticket is booked through Qantas. If what I was told is correct then I cannot upgrade on the Singapore-Dubai and Dubai-UK routes from April onwards even if I book through Qantas and my tickets are for QF flights, because the flights would be operated by Emirates (i.e. "Emirates-metal"). What is Qantas policy about upgrading?

I believe you're correct. Upgrades on apply on Qantas metal for Qantas issued tickets.

The only Dubai-UK route eligible for upgrades will be the London one, operated by Qantas.

However, seeing as you live in Singapore you should be able to continue to upgrade on the SIN-FRA whilst Qantas still flies that route.

You won't be able to upgrade on SIN-DXB, but will be able to upgrade on DXB-LHR (for the QF metal flights only).