CX has been doing this "changing of aircraft equipment" very suddenly the past few weeks. It has been annoying to say the least.

Hope you can change your travel plans... but otherwise, the old seats are not going to kill you. They are 2-2-2 configuration and recline almost flat. You can still sleep on them.

Inflight service remains unchanged. That is what gives CX the edge above above airlines.

If you have a full first class ticket, maybe you'd like to consider taking SQ out of SFO to HKG instead? Your ticket should be fully endorsable.