If you were looking to get a new Windows Phone from AT&T, it's not going to happen (via Neowin). The only listings for Windows phones remaining on the AT&T website are two certified like-new listings for the Lumia 640 and the Lumia 950 - everything else is nowhere to be found.
That's not to say that you can't pick up your Windows phone of choice elsewhere. You can grab pretty much any phone you like from one of several third party retailers, and the Microsoft Store remains to be an excellent choice if you're looking to order online. While AT&T's apparent drop of support for the operating system is disheartening, it's not stopping anyone from picking up their handset.
We don't have any comment just yet from AT&T regarding the lost listings for all of the Windows handsets, but we'll be on the lookout if they start explaining themselves.