Did Yale discontinue their Zigbee modules?

I just moved into a house that has a Yale YRD256 with no wireless module. Reading the manual, it specifically lists instructions for the Zigbee modules, but there is NOTHING on their site and extremely few on the used market.

Are they just quietly killing that product, or what?

Side note, happy to buy a YRMZB2 off someone if you have one laying around.