Down at the bottom of the email in the smallprint they do say:
"
Disclaimer: This offer is being presented to you because you are a ZBrush perpetual license holder. Rest assured, perpetual licenses are not being eliminated. However, perpetual licenses will not receive free upgrades past ZBrush 2022.0.5. Discount is valid for Annual Subscriptions only. "
So from that our perpetual versions are not going anywhere, but no more free updates to it.
But yes, personally I think this email has been exceptionally badly handeled. Offering a half price subscription to software we already have full lisences for, without saying about actual perpetual updates or their costs? A total kick in the teeth!
See other users (including me) frustration here…
Hopefully we can pool information there, as we’re not getting it from Maxon.