Replace atom:modified, atom:issued, and atom:created with atom:updated.
RobertSayre (I'll support this because it doesn't prevent tracking updates more rigorously)
"Updated" is the most useful single date for enabling meaningful sort order. For those who wish to sort by "issued", they can get close enough by caching the first value they see in atom:updated, and sorting by the original value if atom:updated changes. Those who wish to sort by atom:updated can obviously do that too.
There are objections to duplicating dates from dcterms in the Atom core. dcterms does not have anything that matches atom:updated.
Replace sections 5.6, 5.7 and 5.8 with the following:
=== 5.6 "atom:updated" Element === The "atom:updated" element is a Date Construct indicating the most recent date and time when a change was made to the entry which the publisher wishes to bring to the attention of subscribers. Such changes will typically not include minor adjustments like spelling and grammatical corrections. atom:entry elements MUST contain exactly one atom:updated element. The content of this element MUST conform to the Date and Time format defined in [http://www.faqs.org/rfcs/rfc3339.html RFC 3339]. Publishers MAY change the value of this element over time. Consumers MAY choose to sort based on this value. Consumers MAY choose not to display entries until the date specified in the atom:updated element.
If this is the only Date Construct that makes it into Atom, it may be polluted somewhat by "subjective" dates. Note that since it is up to the publisher to decide subjectively whether an update is significant enough to warrant updating this value, even though it is supposed to be an objective date (the actual time when the update occurred), there is some subjectivity built into it.
If the value of atom:updated for an atom:entry changes, consumers MAY choose to continue to sort based on the original value rather than the new value.