There are two tracking systems - v1 and v2.
Version 1 uses HTC-made lighthouses - square-ish design with a flat front. These are compatible with v1 and v2 accessories.
Version 2 uses Valve-made lighthouses, even when supplied by HTC with their Vive products - if it has a curved front, it's v2 (there are two physical variations - the earliest has a sync port & angles on the side). These are only compatible with v2 accessories.
v1 accessories include the original Vive headset & controllers (all-black)
v2 accessories include the Vive Pro/Pro Eye/Pro 2 headsets & controllers (blue), Index headset & controllers, and other third-party headsets/controllers like Pimax.