diff --git a/CHANGELOG.md b/CHANGELOG.md
index 06f73c2..e2f652c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Changed
+
+- The planned CI matrix in `docs/SPEC.md` names `macos-15` instead of `macos-14`, which GitHub
+  retires on 2026-11-02.
+
 ## [0.5.0] - 2026-05-16
 
 ### Added
diff --git a/docs/SPEC.md b/docs/SPEC.md
index afd2651..69b7861 100644
--- a/docs/SPEC.md
+++ b/docs/SPEC.md
@@ -765,7 +765,7 @@ Concretely:
 - [ ] Add `supported_ecosystems` to the version-entry schema as a
       richer counterpart to `supported_platforms`. Same shape; broader
       vocabulary.
-- [ ] CI matrix: add `macos-14`, `ubuntu-24.04`, `windows-2022`,
+- [ ] CI matrix: add `macos-15` (pinned arm64; `macos-14` is retired on 2026-11-02), `ubuntu-24.04`, `windows-2022`,
       `ubuntu-24.04` with `alpine:edge` container, plus
       `freebsd-14` (via `cross-platform-actions/action` or QEMU).
 - [ ] `docs/ecosystems/` with one page per non-mainline target: