And yet it is based on truth. Official means a LU patch where many changes are made, Sony advertises the changes for weeks ahead of time usually, puts an early version of the changes up on test server so people (like Amadeus) can play around with it, and usually announces the date quite awhile before the day they put them on live servers.
Unofficial is usually after a LU horribly breaks something and comes within a few days after a LU with them trying to fix some horrible bug affecting server stability or a huge exploit. This they don't announce ahead of time, we have no idea what is changed in them, and they don't announce them ahead of time.