I've just been informed that the usage of one of the Printing TXT
record keys was changed slightly in Mac OS X 10.3. If you make a
Rendezvous compatible printer, keep reading...
In Mac OS X 10.2.x, if a key/value pair of "rp=queue12" was present in
an IPP TXT record, the following URL would be created...
However, the above URL is not in the proper format for an IPP URL, and
so in Mac OS X 10.3 and later, if "rp=queue12" is present, the
following URL will be created instead...
To workaround this change, you could have your printer recognize both
URL formats, or you could accept the new URL format, and specify one of
the other printing protocols as the highest priority protocol, in order
to stay compatible with Mac OS X 10.2.x.
I will update the Printing Spec shortly to reflect this change. Please
let me know if you have any questions.