Alternate draft for revised versioning proposal

Folks,

I've posted a new "alternate" draft which outlines a revised
versioning policy:

  http://www.w3.org/XML/XProc/docs/alternate/

The key changes:

1. Extra attributes and elements are not static errors.
2. Extra input ports are not errors.
3. Extra output ports are not errors.

The key non-changes:

Fowards-compatible processing still requires the V-previous processor
to download the step library that defines the V-current step
signatures.

Comments most welcome.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | If you haven't found something strange
http://nwalsh.com/            | during the day, it hasn't been much of
                              | a day.--John A. Wheeler