How to update Aperture 3.6 from 6.06 to 6.19 (Nikon D500 RAW support)

Hello everyone

I'm running Yosemite 10.10.5 (see below for details) and it's probably the time that will update to Capitan!

Having just purchased a Nikon D500, I realized that my version (3.6 - RAW 6.06, BUILD 819.4 / DCR 6060 - 194.4 does NOT work with its raw).

By investigating over the net, a friend photographer of mine (he does have Capitan AND Aperture 3.6 RAW 6.19, Build 844.1, DCR 6190 - 221.1) is able to open and work with D500 NEFs, yet I can't find any way to make this minor upgrade neither in Aperture nor in Apple Store nor elsewhere.

I'm kind of reluctant to use Photos which seems much less capable than Aperture, at least on paper. Is there any way to upgrade? I suspect in some way he got a notification to update his Aperture when he was at a lower level to 6.19.. no ?