We all hope to see this:

from Jeh Johnson speech

I do believe that on the present course there will come a tipping point, a tipping point at which so many of the leaders and operatives of al-Qaida and its affiliates have been killed or captured, and the group is no longer able to attempt or launch a strategic attack against the United States, such that al-Qaida as we know it, the organisation that our Congress authorised the military to pursue in 2001, has been effectively destroyed.

At that point we must be able to say to ourselves that our efforts should no longer be considered an armed conflict against al-Qaida and its associated forces, rather a counter-terrorism effort against individuals who are the scattered remains of al-Qaida … for which the law enforcement and intelligence resources of our government are principally responsible.
but when will it become official ?

From the US standpoint (based on what the Federal courts have decided so far), the end of the AQ-armed conflict could occur if (1) both President and Congress agree it's ended; (2) the President declares it's "ended" (in the sense of a ceasefire; e.g., Bush I in Gulf I); or (3) Congress declares it's "ended" by overriding a Presidential veto (say, of a defunding resolution). The appellate decisions, so far, have claimed no judicial authority to end an armed conflict.

On the other hand, substantial opinion in the "international legal community" is that the end of an armed conflict can be determined by "it" - as a matter of customary international humanitarian law.

So, Jeh didn't say anything we didn't already know.

Regards

Mike