Skip to content

licensing.md

Latest commit

 

History

History
140 lines (106 loc) · 6.17 KB

licensing.md

File metadata and controls

140 lines (106 loc) · 6.17 KB
Raw

Station Manager — licensing

This document explains Station Manager's (SM) licence and how it relates to the FT8 protocol implementation it builds on. It is written for three audiences: a curious user evaluating SM, a distro packager considering inclusion, and a contributor who wants to know the licence their PR lands under. If you spot something that looks inconsistent with the policy below, opening a GitHub issue is the right next step — see the closing section.

History. SM was MIT-licensed from its first commit until 2026-05-31, with an elaborate clean-room policy designed to keep it MIT while implementing FT8 from the published specification. That effort is over. SM is now GPL-3.0-only. The reasoning is in docs/decisions/0023-relicense-to-gplv3.md. Earlier revisions of this file described the MIT/clean-room position; git history preserves them.

1. Station Manager is GPL-3.0-only

The full text is in LICENSE at the repository root; NOTICE records the copyright and the derivative chain. The GNU General Public License, version 3 only (GPL-3.0-only) is a strong copyleft licence: you may use, modify, and redistribute SM, but any distributed work that incorporates SM's code must itself be licensed GPL-3.0-only and ship with (an offer of) corresponding source.

The "version 3 only" — not "version 3 or later" — wording is deliberate and inherited; see §3.

Copyright on SM's own code is held by Marc L. Veary (7Q5MLV), the sole author, which is what made the MIT → GPL relicensing possible.

What changed for users and packagers

  • Source up to 2026-05-31 stays MIT for anyone already relying on it. Relicensing is not retroactive on copies already published under MIT — any commit at or before that date, and the v1 branch / v1.0.0 tag, remains usable under MIT terms. From 2026-05-31 onward, main is GPL-3.0-only.
  • Binary distribution carries a source obligation. The RPM and any other binary you redistribute must be accompanied by, or offer, corresponding GPLv3 source. The public GitHub repository satisfies this for tagged source builds.
  • Forks and downstream work must stay GPL-3.0-only. You can no longer fold SM into a proprietary or permissively-licensed product.

2. Why GPL-3.0-only — the FT8 decode path

SM's reason for existing is logging and forwarding QSOs; FT8 decoding is one capability among several. That capability is provided by a companion library, go-ft8 (github.com/ColonelBlimp/go-ft8), which SM links in.

go-ft8 is an explicit WSJT-X/jt9-derivative — it descends from the GPL-licensed reference implementation of FT8 — and is therefore GPL-3.0-only. A derivative of GPLv3 code is a derivative regardless of the implementation language or who read the source; linking it into smd makes the distributed daemon a derivative work, and GPL copyleft requires the combined work to be distributed under the same licence. SM could not link go-ft8 and remain MIT, so SM adopted GPL-3.0-only.

This reverses years of effort that went the other way. SM previously maintained a clean-room boundary (implement FT8 from the QEX 2020 specification paper + the public-domain ref [14] tarball, never from the WSJT-X source) precisely to keep the project MIT. That clean-room decoder never reached jt9 parity and hit a runtime/decode-depth wall; the operator chose the WSJT-X-derived go-ft8 as the shipping decoder instead. With the project now GPL, the clean-room boundary is retired — see §4.

3. version-3-only, not "or later"

go-ft8 is licensed version-3-only. A work that links version-3-only code cannot offer the recipient the GPL's usual "or, at your option, any later version" choice, because part of the combined work forbids it. SM therefore inherits -only. The SPDX identifier is GPL-3.0-only everywhere it appears (LICENSE/NOTICE, nfpm.yaml, package.json).

4. The clean-room boundary is retired

The former policy forbade reading WSJT-X source, ran an "AI-consultation derivation gate" for FT8 constants, and preferred BSD/MIT FFT libraries over FFTW3 to keep the binary unencumbered. None of that applies any more. Now that the project is GPL-3.0-only:

  • Building FT8 on WSJT-X/jt9-derived code is permitted — that is exactly what go-ft8 does.
  • jt9 and the WSJT-X source may be used freely as references, oracles, or derivation sources for GPL code in the SM/go-ft8 family.
  • A GPL'd CGO dependency such as FFTW3 no longer raises a binary- distribution concern, since the binary is GPL anyway. (go-ft8 currently vendors BSD-3-Clause PocketFFT regardless, for its own reasons.)

Contributors touching FT8 should work in the go-ft8 repository under its GPL terms and its docs/WSJTX_DERIVATIVE.md conventions; SM itself links go-ft8 rather than carrying the decoder.

5. Dependency compatibility

GPL-3.0-only can only be combined with GPL-compatible dependencies. As of this relicensing every Go and JavaScript dependency SM pulls in is under a permissive licence — MIT, BSD-2/3-Clause, Apache-2.0, or ISC — all of which are GPL-3.0-compatible, so the combined binary is distributable.

The one thing to check on any new dependency is GPL compatibility. A GPLv2-only, CDDL, or proprietary dependency would be incompatible and is the thing to reject — the licence stays put. (Apache-2.0 is compatible with GPLv3, though not with GPLv2 — another reason SM is on v3.)

6. go-ft8 notices to carry

When a binary that links go-ft8 is redistributed, preserve go-ft8's own LICENSE (GPLv3), its NOTICE, its docs/WSJTX_DERIVATIVE.md derivative- status notice, and its third-party notices (notably the BSD-3-Clause PocketFFT it vendors). SM's own NOTICE points at these.

7. If you find something that looks wrong

If you find a dependency that looks GPL-incompatible, a binary release that ships without a source offer, a stale "MIT" reference left over from the old policy, or any other licensing gap — please open a GitHub issue. The fix is usually one of: replace the incompatible dependency, add the missing source offer, or update this document. Surfacing it is more useful than letting it sit.

Maintained by Marc Veary. Last updated 2026-05-31.