Hello Tom and Ben, the article viewer will always show the most recent published version of an article but we currently don't have a way to identify what has changed in an article since it's last published version.
Regarding the Date Created in the article viewer, we are aware of a defect in the underlying system which is causing the created date to show the time stamp for when the current version was created, as opposed to the time stamp for when the original version was created. We are awaiting a fix for this issue from a third party vendor which should enable us to rectify this in the next couple of months.
Ben, Thank you for informing me about the issue with the email digest, aka PTC Technical Support Subscriptions email; sorry if this has caused confusion, I have reported the behaviour to the team that handle this functionality and they are looking into it.