According to https://portal.msrc.microsoft.com/en-US/security-guidance/ad..., it doesn't look like windows 8.1 received a patch either, and that's still in support. Maybe only windows 10 has ECC support, and therefore any previous versions are not affected?
Also, according to https://support.microsoft.com/help/4534310, it looks like Windows 7 got security patches for this month.