DSD-neo is distributed under the terms of the GNU General Public License v3.0 or later. See LICENSE for the full text.

Legacy ISC-licensed portions from the original DSD author remain identified via SPDX headers in the source tree. These files are GPL-compatible and ship alongside GPL-3.0-or-later code.

The D-STAR radio-header processing path (scrambler, interleaver, Viterbi decode, CRC) was rewritten in 2025 under GPL-3.0-or-later to replace prior GPL-2.0-only contributions.

Third-party and upstream-derived code retains original notices in-place. Vendored ezpwd Reed-Solomon contains GPL-3.0-or-later/LGPL components (see src/third_party/ezpwd/ and src/third_party/ezpwd/lesser.txt), and pffft/FFTPACK retains its bundled notice under src/third_party/pffft/COPYING. Additional embedded provenance-bearing files are summarized in THIRD_PARTY.md.

Some source files currently contain SPDX identifiers together with more specific embedded provenance or license comments inherited from upstream material. Until those headers are reconciled, consult the per-file notices and THIRD_PARTY.md for file-specific attribution and license context. Installed third-party license texts are shipped under share/doc/dsd-neo/licenses/.