Mine is also a 2015.
Dealer told me it would be a simple software update when I bought my truck. They lied to me.
They lied about more than a few things but that one to me was a big one as it's something I really wanted.
The aftermarket has jumped all over this infotainment system! And that's great.
What's not great is they want more for the same upgrade than GM did when the truck was new!!!!!!!
Example: Nav was a $495 option. But could be had from most dealers for $300 if you haggled with them.
Most aftermarket options start at $650 and go to over $1,000!!!!!!!!!! That's down right stupid.
The aftermarket should beat the OEMs prices not double them!