Now we need to work hard for our site/blogs. But these time of crisis is also a great time to earn a lot from it. Adsense will now be more strict on their publishers.
I haven't received anything yet but I must say that I haven't logged into my adsense account for a few days so will have to go and check
This email is a prelude to Google doing some weeding out of low quality sites that have low CTRs. It's a warning that if your site is MFA or low quality content, then you may not survive the clean-up process.