I was in the same boat when I inquired about car play in the 2016 Outback I was purchasing in mid 2015. The salesmen did not know much about it at that time but I purchased the Outback anyway since it wasn't a dealbreaker. I've hoped for a firmware update or upgrade path ever since and when I get the most recent issue of Deive Subaru Magizine an ad in there showed the Apple icons on the Subaru radio and I thought it might have finally happened. But through some research (not complete, btw) it seems CarPlay is still not implemented.
I came up with an alternate plan some time back and it's worked out very well for me. The iPad mini is the perfect size to cover the center bay door in front of the USB connectors. With the right case it fits somewhat snugly but road bumps would dislodge it at random. Enter doublefaced velcro and an old hockey mask cage guard holder I found lying around. I shape the plastic of the cage holder and use the Velcro to put it in place beside the shift lever and now can slide the iPad over top of the door and the face shield holder holds it there. That's just what I found to use but anything that can act as a stay would hold the iPad in place. At first I tried powerful magnets behind each side cover beside the door and narrow slivers of stainless inside the iPad case but they're just was not enough holding power that way.
I got a flat USB to lightning cable and ran it from the USB port, underneath the closed door and into the iPad so it would be direct connect. And plugged my phone which is an iPhone into the PowerPort in the center armrest and connect that via Bluetooth. Benefit is charging while driving and phone connection to system.
Music and Nav from iPad, phone and voice to text from Bluetooth.
It's not perfect and sometimes looses the phone connection but works well overall. The other downfall is if I want local radio or Sirrus radio while nav is active there is no voice through system for Nav directions since the audio is from a different source.
Still hoping for a upgrade path but I would expect it would take the form of a new car. Lol. Why make a firmware change (given the chipset allows) and make pennies if that, or make thousands on a new vehicle
Just my two cents.... cheers!