Microsoft has
clarified that Microsoft Defender will continue to receive updates even on legacy systems like Windows 10 to the "
extent possible".
What this means is that detection and protection capabilities will continue to be added, but if they rely on features not present in Windows 10, then they won't really make an impact. So you're inherently less secure than you would be as compared to a supported system, but it's still better than not having any security at all.
Microsoft has finally ended support for Windows 10, and while customers can opt for the ESU program, those who don't will be protected through Microsoft Defender too... kind of.
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