I’ve had the Bluetooth version for 3 or 4 years, says 1.0 on the tag,
but appears to be identical to the 2.0 and 2.2 bluetooth. The 3.2 has
a bluetooth plus wifi option. The nano is a lot shorter than the rest,
but otherwise the same bluetooth or wifi.
I’ve never had reason to use the bluetooth at all (nor the app). If you want to be able to start and monitor it from the phone app when you’re out, you need the wifi version. If you just want to start and monitor it from your house/yard with the app, get the bluetooth.