All current-generation power meters feature OmniCal, with allows you to swap chainrings without affecting accuracy. Simply torque the chainring bolts to the manufacturers' specification and be sure to set the power meter Zero Offset before every ride. Nothing further is needed.
XX1 Mountain Bike Power Meter: A calibration adjustment may be required when changing from one chainring size to another on this power meter. If you are not changing chainrings, the calibration does NOT require adjustment. (This does NOT include the current XX1 Eagle power meter.
Any Power Meter that uses a CR2450 battery: Any power meter that uses this battery size requires re-calibration when changing to a different tooth count or chainring brand. If you are not changing chainrings, the calibration does NOT require adjustment.
If you're unsure which power meter model you have, please contact Quarq Customer Service. When contacting customer service, please provide the power meter ID located on the power meter spider. The ID consists of 3 letters and 5 numbers such as; ABC12345 or 12345ABC.