Update the Microsoft Defender app on your Windows device

I just got an email notification asking me to

Update the Microsoft Defender app on your Windows device​

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The sender (mydefender@microsoft.com) appears to be legitimate.
I have checked Windows Security on both of my Windows 11 PCs and find all components (including Defender) up to date.
Unfortunately, the email doesn't give any clues as to which device it refers to, but I suspect that it concerns my old Windows 10 PC, which no longer access the Internet.
Does this sound plausible?

Yes, we have the same email here. The link (if you were to press the Update Defender App button) goes to "https://mydefender.microsoft.com/downloadwindows" and the domain appears ok. However Defender App updates usually come from windows update and I won't be pressing the button on the email. Done a windows update on all devices and no defender app updates. I've checked the devices listed on my microsoft account and they are all current devices and no disposed ones.
Seems very strange.

There's a thread about this email on reddit in r/antivirus started 9 days ago. Search reddit on "Update the Microsoft Defender app on your Windows device" (using the quotes) to find it. Consensus there is to be suspicious.