If its an older unit, it's likely a Anikf2. Which means it's more than likely you will be directed to the WB1 bird. Which means you will need a different tria. Which means you will need a service call. Which likely means you (or tech) will need an APA to re-lock to new bird.

Note: if your not in an overlapping beam area, you will never need an APA. I never require one.