Hi, I'm looking to replace my thermostat with a new programmable one, and I'm trying to figure out which ones might be compatible with my heat pump. I'm having trouble determining even what type of heat pump I have. Any help would be appreciated!

Here is the information I have:

On the unit outside:
BDP / Carrier
Product #: 542EBX042000AAAF
Model #: 542EB042

On the existing thermostat inside:
Payne Heat Pump
BDP Co
34427DP120
3AAB82B14C2

Wiring:
8 wires
C: Black wire
R: Red wire
O: Orange wire
G: Purple wire
Y: Yellow wire
W1: White wire
W2: Brown wire
E: Blue wire

I believe the unit was installed in the early 1980s. Please help!

Do I have a single or multi stage heat pump?
What do the wire colors mean?
What type of programmable thermostat should I be looking for?

Sorry for the lengthy post, just wanted to include all information. Thank you for your help.