Python adds a third 3.15 release candidate to fix lazy-import blockers

Python 3.15’s final release has been delayed to October 9 while the team tests fixes for last-minute lazy-import blockers. The extra release candidate, 3.15.0rc3, includes bug fixes, build improvements and documentation changes. The team says the ABI is now fixed for the series and encourages package maintainers to test compatibility and publish Python 3.15 wheels.

Python Insider · Oct 2, 2026

Why it matters

Library maintainers have another opportunity to catch compatibility problems before users upgrade.

More context

Try rc3 in a separate test environment and run your package’s import, extension and test workflows. Report regressions through the Python tracker; the announcement links downloads and the preparation guide.

Keep in mind

This is a preview release and is explicitly not recommended for production. October 9 is a scheduled date, not a guarantee; 1min has not tested third-party package compatibility.

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