Those PMs were there a week ago.
I
strongly doubt that. I just checked the backups, and there are no PMs to/from you which exist in any PM backups but not in the live database. So I am 99.9% sure that any missing PMs were deleted by all parties prior to the oldest backup from ~6 months ago.
You are of course free not to trust me.
Theymos - are you looking into the logs to see what happened to the PMs? Would it help if I produced a list of PM subjects and dates that were deleted?
You can send them to me and I'll see if they're in your inbox and you're just not finding them, but if not, there aren't really any additional logs to look into. We obviously don't log subjects of PMs deleted from the database -- that'd be a privacy disaster.
You say that you saw the PMs a few days ago. If this was more recent than roughly June 15 and you find the URLs in your browser history, I could give you the corresponding server access logs, though whether or not this would actually show anything useful is unclear, since the only data logged about the response is the status code and size.
Don't you have data that the PM had been deleted by users, the sender, or the receiver?
SMF doesn't log the time of a deletion, and it'd probably be a greater privacy cost than a usefulness benefit to add it.
Do you store this data for 6 years only in cases where the user has not adjusted personal settings?
Of course.