How many zones does the VISTA-128FBP support, and what expansion options are available to reach the maximum zone count?

The VISTA-128FBPT supports a maximum of 128 zones (Page 5) [1].

While the manual does not provide a specific list of expansion hardware, it identifies that the system monitors protection zones using 5800 series wireless devices via RF receivers and a polling loop (Page 6, 60) [1].