First offered in September, the optional $100 antenna added 15" height to a basic WiFiRanger, and the 8.5dB gain delivered nearly 4x the signal strength of the stock 3dB antenna offered with the WiFiRanger MobileTi.
But ever since WiFiRanger switched to offering the 6dB-equipped Elite instead of the MobileTi, the XT was no longer nearly as compelling of an upgrade.
The custom XT Antenna is still warrantied of course, but simply is not available for purchase. Since the standard antenna of the Elite is already high-gain at 6dB, the XT Antenna became less appealing and was always extremely expensive to manufacturer/stock.
And indeed - for most usage scenarios, the Elite's stock antenna and powerful radio are probably plenty.
But if you had your heart set on a towering XT on your roof or up a mast, unfortunately, you are now out of luck.