Until your anti-virus adds this Registry key, you aren't getting any more Windows security updates

This has been mentioned in the last few days but like probably some others I had assumed it was just to do with the Meltdown and Spectre vulnerabilities, well that is wrong, read on if you are not sure.
 
What a mess.
 
January 9th, 2018  By Graham Cluley
 

 
You're security conscious. You're aware of the threats. You like to run a tight ship.
 
You keep up-to-date with the latest security patches, and - of course - you run an up-to-date anti-virus.
 
Well, things just got a heck lot more complicated for users of some anti-virus programs.
 
That's because Microsoft has said that customers who are running certain anti-virus products will not receive its bundle of January 2018 security patches (including mitigations against the Spectre and Meltdown CPU flaws) unless their products certify that they don't make unsupported calls into Windows kernel memory.
 
Full Article.