Install AcelleMail on Debian 12 (Bookworm)

No real reason, the guides just predate MariaDB being common. Debian 12's MariaDB 10.11 is fine. Only thing: create the database as utf8mb4 with utf8mb4_unicode_ci, don't trust the server default.

Worth noting Debian 12 ships systemd-resolved too, so this isn't just an Ubuntu 22+ thing, the stub listener sits on 127.0.0.53:53 out of the box. The conflict only bites if you put a real resolver on the box (unbound, dnsmasq, a local BIND for reverse lookups), which a lot of people do once they start doing their own bounce and blocklist checks. The bounce handler itself just reads IMAP, it doesn't want port 53. I'll add it to the article as a note under the prerequisites section rather than a step, since it's conditional. One correction I'd make to your snippet: after editing /etc/systemd/resolved.conf you also want to point /etc/resolv.conf somewhere real, otherwise the box loses DNS entirely once you restart the service. Symlink it to /run/systemd/resolve/resolv.conf or write your own.

No supported headless install path today, so on Debian 12 the wizard is still a manual step. It's on the list, and the shape we want is an artisan command that takes the same inputs the wizard collects (DB creds, app URL, admin account) so Terraform can bake the .env and run it in a provisioner instead of a browser. If you want to try it before that lands: the wizard's whole job is writing .env, running migrations, and creating the first admin. Those are all reachable from artisan, and the install screen is gated by a marker file the wizard drops at the end. People have wired that up by hand. It works, but it isn't documented and I'm not going to promise the marker path stays put across upgrades, so pin your version if you go that route. Tell me what your Terraform module needs to pass in and I'll make sure the command signature covers it.