Local dealer told me they had done a few android auto updates on 2015s so I took mine in on Saturday. Four hours later the update was supposedly complete. Started it up and nothing was different. Same UI, no icon changes. Plugged in my Samsung and nothing happened. Pretty disappointed. It amazes me how GM passes down these updates to dealers with little to no information on compatibility. Dealer was convinced it had updated. I tried to tell them nothing was changed and just received a shoulder shrug in return.
Have them quote you the following:
2016 HMI 2.5 module
2016 Radio receiver
2016 USB port located on the cup holder area.
for parts searching use a 2016 Vin # with the same options you have.
Then have them install the new equipment, update your vin# and load the latest firmware with Android auto to the new HMI module.
Apple carplay and Android will not work with 2015 HMI module, receiver and USB hub. The new equipment is all Apple approved and the HMI goes from 2.0 to 2.5 with a faster processor.
The dealer of course will charge you retail cost for all 3 units which will be over $1000 (w/Nav) plus labor for programming the Vin # and installation.
As for GM passing info to the dealers, I think it up to the dealership/management to properly informed and train their staff of these TB that are published from GM. The information is there.
Or go to MVI and buy everything from them- that's what I did!