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Python 3.15.0rc2 final release candidate locks ABI ahead of October 2026 final
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Python 3.15.0rc2, the final planned release candidate, ships with approximately 144 bugfixes and freezes the ABI for the 3.15 series before the stable release on 2026-10-01.
The ABI freeze means binary wheels built against this candidate will work with all future Python 3.15 releases, so maintainers can publish 3.15-compatible wheels now with confidence. The release also confirms the feature set including explicit lazy imports, frozendict, UTF-8 default encoding, and an upgraded JIT compiler showing 8-9% performance improvement on x86-64 Linux.
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Python 3.15.0rc2 is the final planned release candidate, with only clear bug fixes allowed before the final release on 2026-10-01.
The ABI is now frozen for the 3.15 series, meaning binary wheels built against this candidate will work with future Python 3.15 versions.
Major additions include explicit lazy imports, frozendict and sentinel built-in types, UTF-8 default encoding, and an upgraded JIT compiler with 8-9% performance gains on x86-64 Linux.
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