Update: I wasn't successful in finding RA4/VP4-CA firmware files. But somewhere along the way I read that someone had updated successfully to 18.x.x on a Canadian radio from either 17.11.x or 17.43.x. So I kept digging and so far, I'm up to 7.11.01 on a VP4-CA radio by doing the following:
I started with:
VP4 (NAV Version) from Canada(CA) - P/N: 68258675AF
Starting with SW version: 15.30.2
I found some MY16 files for VP4 radios, but they were all North America (NA).
Versions I found were: 15.44.4, 16.33.29, 17.11.07, and eventually 17.43.01 - Again, all NA.
So I found a 8gb USB thumb drive, formatted it to Fat32, and started with 15.44.4 and worked my way up.
Since these take a little while, I hooked up a battery charger to my truck. Got inside with key fob and closed the drivers door. Put my push button start into Run but NOT starting the truck. Inserted USB drive in and waited for the screen to tell me whether or not the image was good for my radio - and the display screen indicated that it was good and a Yes/No option if I wanted to continue. Radio began to check the ISO and go into each area the firmware was updated for this version. Finished, restarted the radio, and I left the USB drive in until it asked me AGAIN if I wanted to upgrade my radio - but this time it showed that I was on 15.44.4 and same question was up asking if I wanted to upgrade to 15.44.4. To me that indicates the upgrade is complete so this time I selected NO. I then checked system settings, and indeed I was no longer on 15.30.2, but now on 15.44.4
So I repeated the same steps - with one change. I put down all the windows after putting the truck into Run on my pushbutton start. Got out of the truck leaving it in Run (but not running), closed the drivers door and then reached in through open passenger window inserting the USB key in center console and then selecting YES to do the next upgrade when the question came up on the screen. TOO HOT inside the truck.
I do want to mention that during the 17.11.07 update, I stuck around and notices that once it applied 3 of 15 and then again on 4 of 15 updates the radio reset/rebooted. But on each one it did NOT repeat those steps again (but did repeat 1 of 15 and 2 of 15 updates). The rest of the update went as expected.
So at this point I'm on 17.43.01, I can see both bed camera button and tailgate one and they both work when selected. NAV when I select the MAP icon dose say it needs to calibrate and take it to a major road to start that, but no buttons to push. Probably just a sync thing. Radio works well and kept all my channels on FM, so that's good. I'll test it out more in a few days, but very happy I didn't have to pay the dealership $480 to get to the min FW version just to update the maps.
Who knows, maybe I'll see if I can find the 18.45.01 MY16 NA file and go up to that..
Hope this helps others!