How long time supported?

Hello all.

I have a RT-AC68U and are wondering: How long time shall I expect my router getting updates, like any updates, from ASUS, Merlin, Tomato, DD-WRT maybe some I don't know about??

I hope getting updates to minimum 2020, so I can at that time look for an ax-router.

But as long I can get updates for my router, I will keep it. For now I have only one ac client anyway.
All other clients are either G or N.
And will go minimum 3 years before I am getting an ax client.

Regards