John's plan, 2026-09-19: stop the Enterprise server and the ihasmail container, install the fork at its own path, copy the data across, bring up INBUXA Admin and the new webmail, and every account carries on. That is a better shape than the in-place swap this draft assumed, because the rollback becomes a service swap rather than a restore: the old install and its data are untouched, so going back is stopping one unit and starting another. What it costs is whatever the fork accepted in between, since the two stores diverge the moment the fork starts. It buys one failure the in-place swap couldn't produce: both servers on one set of ports, each with its own store, if a reboot brings the old unit back. So the unit is disabled, not just stopped. Also written down: the front ends' OAuth clients travel inside the store, so a front end that keeps its client id and redirect URIs keeps working and one deployed fresh needs them set up, which fails looking like an account problem when it isn't.
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.