If I understand you correctly, I'm able to tell you that this feature is already available in 4.5. If you're editing a news article or other content item, if you click on the "Publishing" tab, there is a field called "Override Created Date." By default, it will display the date when you first created the item, but you can easily type in another date using this format-- YYYY/MM/DD For instance, I have a database of reviews that I'm posting
now, but were written a few months ago and I have always been able to change the date to when it was actually written and not when I posted it. It
is handy!
