Update the Airport Base Station. If Apple is going to continue selling it as ‘new’, then it should support 802.11ac like most (or all) of their other products do.
Agreed. I don’t see why my phone can have 802.11ac but the AirPort Express can’t. Well I think the answer is they wanted to push people towards the huge, ugly, white monolith that is the AirPort Extreme or Time Capsule. An example of Apple being hostile to users.