Proposed resolution to the app:updated/app:edited problem. Tim says we need to get consensus before anything goes in to the spec regarding app:edited

This uses the app:edited element but introduces the concept of a "synchronization feed" ordered by app:edited to supplement the collection's primary feed ordered by atom:updated





10. Listing Collections

   Collection resources MUST provide representations in the form of Atom
   Feed documents whose entries represent the Members in the Collection.
   Each entry in the Feed Document SHOULD have an atom:link element with
   a relation of "edit" (See Section 11.1).
   Clients MUST NOT assume that an Atom Entry returned in the Feed is a
   full representation of a Member Entry Resource and SHOULD perform a
   GET on the URI of the Member Entry before editing.
10.1 Collection Sort Order

   The entries in the collection's Atom Feed MUST be ordered by their 
   "atom:updated" property, with the most recently updated entries
   coming first in the document order.
   Clients SHOULD be constructed in consideration of the fact that 
   certain types of changes to an entry might not alter its atom:updated 
   value and will not affect the position of the entry in a collection.  
   It is the responsibility of the server to determine what constitutes a 
   "significant" change as discussed by Section 4.2.15 of [RFC4287] 
   although the server can allow the client to specify the value of 
10.2 The "app:edited" Element
   Ordering collections by atom:updated means that some modifications 
   to a collections members might not be readily apparent to some 
   editing clients that require finer-grained notification of when an
   entry has been modified in ways that the server considers insignificant.
   To address the needs of such clients, the entries in the collection's
   Atom Feed SHOULD contain an app:edited element.
     appEdited = element app:edited ( atomDateConstruct )
   The "app:edited" element is Date construct as defined by [RFC4287]
   whose value indicates the most recent instant in time when an entry
   was edited, including when it was created.  For the purposes of this
   specification, an entry has been "edited" only if the value of any of its 
   elements or attributes have changed or, in the case of media
   link entries, a linked media resource has been modified in any way. This
   definition purposefully excludes superficial modifications to an entries
   XML infoset such as using a different namespace prefix and adding or stripping
   insigificant whitespace.
   Entries MUST NOT contain more than one app:edited element.
10.3 Synchronization Feeds
   A collection MAY choose to offer an additional Atom feed listing its 
   member entries sorted by their "app:edited" property with the most 
   recently edited entries coming first in the document order.  Such feeds
   are called "Synchronization Feeds" to reflect their intended use as a
   reliable means of detecting and coordinating all modifications to a collections 
   membership regardless of their "significance".
   Every entry in the Synchronization Feed MUST contain an app:edited element 
   and MUST otherwise meet all of the requirements of the collections primary feed.
   The availability of a Synchronization Feed is advertised within the 
   collection's primary feed using a link element with a rel attribute value of 
   "sync" as in the following example.
     <feed xmlns="">
       <link rel="self" type="application/atom+xml"
             href="" />
       <link rel="sync" type="application/atom+xml"
             href="" />

10.4 Collection Paging

11.3 The "sync" Link Relation

   This specification adds the value "sync" to the Atom Registry of Link Relations
   (see section 7.1 of [RFC4287]). The value "sync" specifies that the value of
   the href attribute is the IRI of a Synchronization Feed as described by 
   Section 10.2.  The meaning of a "sync" link relation appearing anywhere other
   than within an atom:feed element is undefined. An atom:feed MUST contain no
   more than one "sync" link relation.