The Feed History draft has been updated to -02;
http://ftp.ietf.org/internet-drafts/draft-nottingham-atompub-feed- history-02.txt
The most noticeable change in this version is the inclusion of a namespace URI, to allow implementation.
I don't intend to update it for a while, so as to gather implementation feedback.
Cheers, -- Mark Nottingham http://www.mnot.net/