There is a confusing error on the first page of the IPP/1.1 Model and
Semantics and IPP/1.1 Encoding and Transport. The date under the authors
names is 1998, not 1999. All other dates were changed to 1999: Copyright
on the first page, expires on the bottom of each page and the date on the
top of all pages but the first.
This error is consistent on the .doc, .pdf, and .txt files, including the
Internet-Drafts just announced by the IETF.
Sorry for this confusion.