That currently looks like where the cut off point is, so only Haswell and newer look likely to receive Intel fixes.
It won't make any difference if the motherboard manufacturers won't do the work to integrate the BIOS fixes. At the moment, Asus have only committed to going back as far as X99, and only one of those. That's pretty poor from one of the world's biggest motherboard manufacturers.
Another example of sub-standard customer service from Asus.