Late last month, ISIS blew the symbolic mosque where the caliphate was declared in 2014. Mosul was finally conquered. Its leader, Abu Bakr al-Baghdadi, was allegedly killed last May. Raqqa, ISIS' "capital" is surrounded and its fall is just a matter of time.
What has to happen to declare ISIS as defeated? E.g. which are the conditions needed so that the Wikipedia entry can be changed from "ISIL is ..." to "ISIL was ..."?
To avoid opinionated answers, I would like answers to be based on historical experiences, for instance, in comparison with organisations like ETA, IRA, etc.
Naturally, there are always dissident opinions that would declare organisations like ETA or IRA still active, but I think a sort of consensus (or maybe the authoritative opinion of some international or multilateral body) is enough for our purposes.
Update: given recent developments (i.e. the almost complete wipe-out of the territorial caliphate in Syria and Iraq), it's increasingly evident that Isis will remain a force to be reckon, at least in the sense of standard terrorist acts. As an ideology, it might never, at least any time soon, be defeated.