Builds on PaceAppModified2 to spec that collections must be sorted by the modified datestamp.
Provides an alternative to PaceConfigurableCollectionOrdering, PaceConfigurableCollectionOrdering2, and RemoveMustOrderCollectionsByUpdated. These three either leave sort order undefined, or allow multiple different sorts. This is thus a happy middle ground option.
Sorting collections by their last modified stamps (whether it be named app:modified or atom:modified) makes it possible to short circuit scanning for changes in the collection. This makes the protocol more efficient for performing syncs, as well as simply scanning for changes as an oversight activity.
Sorting by atom:updated will result in changes (marked as being insignificant for the audience) being buried in the feed, when those changes may well be important to the authors/editors.
Leaving sort order undefined would require scanning all back pages of the collectioon to find changed entries. Tedious, time consuming, and bandwidth wasteful.
In section 9, replace the second paragraph with:
The entries in the returned Feed MUST be ordered by their 'app:modified' property (Section 11.2), with the most recently modified entries coming first in the document order.
Adds a new property to Atom Entries; equivalent to the Last-Modified HTTP header.
This is based on ThomasBroyer's PaceOrderCollectionsByAppModified which was closed much before the recent discussions and realisations that sorting by modified is useful. This pace updates PaceOrderCollectionsByAppModified for spec-09.
If PaceAppModified2 gets up, then obviously app:modified should be specced as atom:modified.