|It's a good question, but I wouldn't count on being able to put 6.3 "on" Audrey. To my knowledge, no one ever got any other operating system onto the Audrey, which is based on QNX 6.0.|
Having said that, it is quite possible to run apps from 6.1 on the Audrey by updating some of the libraries, and in some cases mounting directories from 6.1 on the Audrey via a network. I image the same sort of thing might be possible for other versions of QNX, but judging from the lack of activity here lately, it looks like most of this sort of hacking activity has stopped. Personally, I still use my Audreys all the time, but as dedicated MP3 players running phjuke.