NEST wire question

Hi all, Have a new Heat Pump being installed next week and already have my NEST purchased. Old Trane system has a W wire and an X2 wire (not jumpered) which I believe is just manual EM heat if the compressor fails. NEST support told me I'm compatible if I don't need the X2 wire. Can I hook the X2 to W2/AUX? I'll have Rh, W1, Y1, G, C and O/B but nothing in W2/AUX or Rc (which I know is jumpered to Rh for heat pumps). Both old and new systems are all electric with heat strip backup. NEST says they don't handle EM heat, but I'm confused by this statement on their site...

"All heat pumps need a supplemental heat source when the temperature gets cold outside (usually below 35ºF). This is called second-stage or auxiliary heat and is usually controlled by the wire labeled AUX/W2 on Nest."

I don't have anything connected to W2/AUX.

Just W to W1.

May call them back to verify, just wanted your opinion. Thanks.

Since I believe W is the heat strips and does go to W1, the NEST people said to put X2 in W2/AUX and if it didn't work, just take it out.