Specs: what may carry the Stalwart name, and when it stops

Two decisions §2 implied but never settled.

§2.4 said no "Stalwart" in UI text; §2.6 requires the startup banner, the
JMAP implementation string and OpenTelemetry's service.version to name the
base. Taken literally, the first would strip exactly what the second exists
to keep. Version and build metadata are now exempt, with the distinction
written down: §2.4's first bullet governs identity, the new one governs
provenance.

A second bullet covers material outside the product. The name appears with
its trademark attribution; the fork relationship is stated once in the
provenance or license section; the migration path names the server it
migrates from, because an operator searching for it has to find it. The base
version stays out of taglines, page titles and social previews, where it
reads as a source identifier rather than a fact. No comparison in either
direction: what INBUXA offers is stated on its own terms.

§2.6 said the base drops out of the version string "when it happens", which
left someone judging the moment. The trigger is now the first release that
isn't a rebase on an upstream tag. Because the reason for publishing the
base is one-way store conversion, and that outlives the string, the
amendment routes it to the upgrade documentation rather than letting it go.

§8 no longer asks whether the fork follows upstream's version numbers. §2.6
answered that on 2026-09-18: it has its own.

docs/spec/SPEC.md

@@ -201,6 +201,25 @@ depends on `store` and can't be called from it (`features/scale-out-storage.md`)
   capability `urn:stalwart:jmap` and the `x:` object names. They're
   interoperability, not branding, and renaming them breaks every existing
   client. Anything the fork adds uses its own namespace (open: which one).
+- **Version and build metadata are exempt from the first bullet** (added
+  2026-09-19). `inbuxa --version`, the startup banner and events,
+  OpenTelemetry's `service.version`, the JMAP `implementation` string, release
+  notes and the strip report all name the Stalwart base, as §2.6 requires.
+  That is a factual statement about what was compiled, not a name the product
+  calls itself, and the two bullets don't conflict: the first governs
+  identity, this one governs provenance. A reader who takes "no Stalwart in
+  UI text" literally would strip exactly the string §2.6 exists to keep.
+- **Public material names it once, as fact, with the mark attributed** (added
+  2026-09-19). Where the name appears outside the product — the site, release
+  announcements, documentation — it carries the attribution: Stalwart is a
+  trademark of Stalwart Labs LLC, and INBUXA is not affiliated with or
+  endorsed by them. The fork relationship is stated in the provenance or
+  license section, and the migration path names the server it migrates from,
+  because an operator searching for it has to find it. The base *version*
+  belongs with the operator-facing material above — not in taglines, page
+  titles, hero copy or social previews, where it reads as a source identifier
+  rather than a fact. No comparison, favorable or otherwise: what INBUXA
+  offers is stated on its own terms.
 
 ### 2.5 Packaging
 
@@ -254,9 +273,18 @@ Decided 2026-09-18.
   next date), but as its own milestone: a merge dry run, a strip-report
   comparison against 0.16, and an upgrade test on a copy of real data, because
   it will almost certainly bring a one-way store migration.
-- **Diverging from upstream** is expected eventually, though not soon. When it
+- **Diverging from upstream** is expected eventually, though not soon. The
-  happens, the base drops out of the version string and nothing else about
+  trigger is named, so nobody has to judge the moment (added 2026-09-19):
-  versioning changes.
+  **the first release that is not a rebase on an upstream tag.** While a
+  release still starts from `stalwartlabs/stalwart` at a named version, the
+  base is a fact about how that release was built and stays in the string.
+  The release that no longer does — because merging upstream has stopped
+  being how the fork is built — drops the parenthetical from `--version`, the
+  banner, `service.version` and the JMAP `implementation` string in that same
+  release, and its release notes say why. Nothing else about versioning
+  changes. The reason the base was there does not expire with it: whichever
+  store format a release converts to is stated in the upgrade documentation,
+  which is where an operator about to convert their data is already looking.
 
 ## 3. Clean room
 
@@ -564,7 +592,6 @@ the tenant administrators' own view is not yet recorded
 - Whether the installer stays its own repository or joins the fork's.
 - Governance: solo, or set up for outside contributors from the start
   (contributing guide, sign-off on contributions).
-- Whether the fork follows upstream's version numbers or has its own.
 - The Enterprise License text (`LICENSES/LicenseRef-SEL.txt`) stays while
   upstream files still name it in their headers (`AGPL-3.0-only OR
   LicenseRef-SEL`, 1,112 files at v0.16.22). Deferred (John, 2026-09-18) until