jcoffey-dev
3e69b6139f
John, 2026-09-19, on both counts. The old install is kept, shut down, not removed: its unit installed and disabled, its store read-only, started again if a rollback is ever wanted. When it stops being worth the disk the tool asks — keep or delete — rather than deciding, because it does not remove the thing its own rollback depends on. And the new stack depends on nothing in it. That is the shape's purpose: /opt/stalwart is a reference, everything needed is copied to new paths, and when it goes nothing notices. Nothing in the fork works against that — inbuxa.service substitutes its own prefix, no path names the old tree, and certificates and ACME keys are in the registry inside the store — so a dependency, if one appears, was made by hand during the move. Which is worth proving rather than asserting, and reversibly: nothing open under the old tree, then rename it and leave it a day under real traffic. Deleting proves the same thing and cannot be undone. Two corrections this forces. The rollback has to make the original store writable again first: the guard of step 3 blocks the Enterprise build exactly as it blocks the fork, and finding that out during a rollback is the worst time. And the copy has to be chowned — rsync -a preserves ownership, so it arrives owned by the old service user while the unit runs as User=inbuxa. Also drops the stale "untested" wording about carrying the data back. It was tested; it is impossible.
A complete mail and collaboration server, every feature included, under the AGPL
INBUXA is a mail and collaboration server: JMAP, IMAP, POP3, SMTP, CalDAV, CardDAV and WebDAV, in one Rust binary, with ihasmail as its web front end. It is a fork of Stalwart. Project site: inbuxa.org (not up yet).
Stalwart ships some features only in a paid Enterprise Edition: multi-tenancy, masked email, undelete and others. INBUXA ships everything to everybody under the AGPL-3.0, rebuilding those features independently and without using any of Stalwart's Enterprise code.
Status: in development, not released. The fork builds, passes its unit tests, and runs as a working mail server. The Enterprise features are being specified and haven't been rebuilt yet. Don't run it in production.
What's different from Stalwart
- Every feature, one edition. No license key, no edition checks, no
upsell. See
docs/spec/SPEC.md§4 for the features being rebuilt, anddocs/spec/features/for each one's specification. - Webmail and administration by ihasmail, as a separate service that can run beside the server or elsewhere. Stalwart's own web interface is removed, so there's no web front end on the mail host.
- Clean-room rebuilds. Enterprise-only code is stripped from every
upstream release before it's imported. The rebuilt features are written
from specifications that use only public sources (
docs/spec/SPEC.md§3).
How the fork is kept
Upstream releases arrive as stripped snapshots, never with upstream's git
history, which contains Enterprise code. tools/fork/strip.py builds each
snapshot on top of upstream's own ossify.py, then verifies it independently.
The report for every import is in docs/fork/strip-reports/. See
docs/spec/SPEC.md §2.
Building
cargo build --release -p inbuxa # the binary is target/release/inbuxa
docker build -t inbuxa . # or the container image
Settings are read from INBUXA_* environment variables. An existing Stalwart
install's STALWART_* variables still work, with a warning to rename them.
New installs keep their data in /var/lib/inbuxa and logs in
/var/log/inbuxa. Existing installs keep the paths their configuration
already names, so none of their data moves.
License and credits
INBUXA is free software under the GNU Affero General Public License, version 3.
It is a fork of Stalwart, copyright © Stalwart Labs LLC. Upstream's copyright notices are kept on every file they cover. Stalwart's files are dual-licensed AGPL-3.0-only or Stalwart's Enterprise License, and INBUXA takes them under the AGPL-3.0 only. A few of those files also carry code from other projects under MIT or BSD licenses, which stays under those licenses; THIRD-PARTY.md lists it with its notices. "Stalwart" is Stalwart Labs' name. INBUXA isn't affiliated with or endorsed by Stalwart Labs.
The INBUXA mark reuses ihasmail's cat-and-envelope artwork.