“We’re discontinuing the Apple Thunderbolt Display. It will be available through Apple.com, Apple’s retail stores and Apple Authorized Resellers while supplies last. There are a number of great third-party options available for Mac users,” said an Apple spokesperson.
Limited availability of the display first sparked hope of a refresh back in May. Then earlier this month it was reported that Apple was working on a new Thunderbolt 5K display that featured an integrated GPU. However, Apple didn't unveil the rumored monitor at WWDC 2016 and discontinuing the current display without updating it suggests that it may be a while before customers are able to purchase a next generation model.
There is still stock left of the Thunderbolt Display. If you really need one you should grab it now!