Enthusiast abandons self-hosted Microsoft Exchange after 27 years, moving mailboxes to Microsoft 365

A homelab enthusiast is retiring a Microsoft Exchange installation that began with Exchange 5.5 on Windows NT 4 in 1999. After migrating mailboxes to Microsoft 365, he kept Exchange 2019 running to relay local hardware and software alerts. Postfix on Ubuntu Server LTS will take over, with plans to add STARTTLS, Let