The last question I could find was from Apr 2012 where the top answer said the feature will eventually work
Yet it is now 2015, and the feature has neither been removed nor been implemented, just left as a stub with a GUI and no logic behind it
Why keep a GUI for a feature that does not, and has never, existed?
I recall reading some discussion about improving this feature in the Dev/QA mailing list relatively recently (late 2014 / early 2015) however I cannot locate the thread. There is still a desire to improve the facility, but it will not likely happen quickly. The related bugs are fdo#54242 and fdo#62637.
Note that an update is a bug fix release (x.y.z) while an upgrade is a feature release (x.y).
Here it is October, 2017, and, as far as I can tell, it’s still not working…