This is your reminder to read the Upgrade Guide before spontaneously running sysupgrade.
Post upgrade, I was curious why I couldn’t send/receive any e-mail.
After frantically scouring through man pages I realized that opensmtpd-extras,
the package I was using to read aliases/virtuals/credentials, had been deprecated!
As of OpenBSD 7.6, opensmtpd now uses the package opensmtpd-table-passwd to do this.
If I had simply read the Upgrade Guide, I would have realized this before wasting half an hour!
Thankfully, opensmtpd-table-passwd is a drop-in replacement that doesn’t need any additional configuration.
Hope this help!