Microsoft Exchange Server 2016 and 2019 enter their 'permanently vulnerable' era

Microsoft has warned customers still clinging to Exchange Server 2016 and 2019 to consider the software "permanently vulnerable" as November's security fixes arrive for Subscription Edition (SE) alone. The warning appears in the release documentation for November's Exchange Server SE security update. Looking for Exchange 2016 and 2019 information? Tough.

Summary from The Register Security.