In the rainy season, the rain falls ... and anyone can predict this.
But if there is a drought this year, how do you know which day it will rain?
Canonrumors usually have some concrete information a few months before the launch of cameras, and some specifications when a week is missing for the date. So far nothing concrete from 7D Mark iii.
I'd say, what is known at this source (canonrumors.com) is summed up in the "Buyers Guide":
http://www.canonrumors.com/buyers-guide/
And as we've read rumors before about a 7D3 coming this year the latest stuff says it won't come before 2018.
So the only way to proceed is to continue monitoring the rumors and see if there is an accumulation of 7D3 rumors and updated spec lists.
I haven't seen either, have you?
So I would expect another year to pass.