MacOS::CLT.outdated? only compared clang build numbers, but Apple's builds can go backwards between releases: the Command Line Tools 27.2 package (27.2.0.0.1792148227) ships clang 2100.3.34.1, below the 2100.3.34.2 in 27.0, so brew doctor on macOS 27 said a newer release was available and recommended downloading 27.0. A package receipt whose release is newer than MacOS::CLT.latest_version is now treated as current; otherwise the clang check still runs, so a receipt for the recommended release with an older compiler and installations without a receipt are still reported.

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Codex (GPT-6 Astra) wrote the change and tests, checked that the new examples fail without the change, compared brew doctor output before and after on an affected macOS 27 machine and ran brew lgtm. Claude Code (Opus 5.5) reviewed it, suggested the older-release example after finding that replacing > with != still passed every example, checked the final examples against that and other mutations of the guard and confirmed that the patched MacOS::CLT.outdated? returns false on the same machine.