Apple has stopped selling the last two products in its AirPort networking line, the AirPort Extreme and the Time Capsule, marking the end of an era.
The company officially discontinued those products and the AirPort Express in April, but said it would keep on selling remaining inventory until it was gone. The only way of getting one of the peripherals now is used or through a third-party vendor, as long they have their own stock.
Apple has promised continued software/firmware updates for the AirPort line in order to fix security and stability problems. An August update for the Express added AirPlay 2 support.
The company reportedly dissolved its AirPort division in 2016. Even at the time the development wasn't a surprise, as the AirPort Extreme and Time Capsule saw their last major refreshes in 2013, and the Express in 2012.
In place of its own Wi-Fi routers Apple has chosen to carry third-party models like the Linksys Velop.