The following thread:
has an official answer (from Jeff Atwood♦) which says:
There is a checkbox to opt out of favorite notifications now on the preferences tab of the user page.
I couldn't find the cited checkbox option (did I miss something?). Since it is a 3.5 year old thread this feature can have changed (here are two other old threads marked as duplicates from the previous one).
Regarding situations where status-completed answer does not work anymore, what is more appropriate action to take if one wishes to update/solve/suggest the subject:
Some options I can think of are:
- ask another question and explain why it is being asked again,
- put a bounty in the original thread and ask for updated answers,
- flag for moderator attention, request a rettag and edit the accepted-answer emphasizing it is outdated,
- leave a comment to the OP asking him/her to remove the accepted-answer status,
- combinations of above, other?.
This is not the main question, but I would also appreciate any guidance about how to do to stop receiving favorites notifications.