Python 3.15 is a conservative release that hides two big shifts. the final candidate, rc2, landed…
python 3.15 is a conservative release that hides two big shifts. the final candidate, rc2, landed september 1 with pep 814's frozendict and opt-in lazy imports for faster startups, while free threading finally meets real workloads.
the boring release is the one that ships.
Context
The Python 3.15.0rc2 page says release date September 1, 2026 and calls it the final 3.15 release candidate, with around 144 bugfixes from 76 contributors since rc1, and lists PEP 810 (explicit lazy imports through a lazy soft keyword, with -X lazy_imports and PYTHON_LAZY_IMPORTS options) and PEP 814 (built-in frozendict) among its highlights. It scheduled 3.15.0 final for October 1, 2026. The What's New text lists PEP 803, 820 and 793 on a stable ABI for free-threaded builds.
As of September 1, 2026 the final candidate wording was correct. After the note, the 3.15.0rc3 page (October 2, 2026) says last-minute lazy-import release blockers postponed the final to the following week, scheduled for October 9, 2026, with about 156 bugfixes since rc2. That supersedes rc2 as the final candidate and does not retroactively refute the note. Opt-in lazy imports is supported. A statement that free threading meets real workloads was not found, and is the author's take. The PEP texts themselves were not read.
Watch next
- 3.15.0 final on its scheduled date, the lazy-import blocker resolution, and free-threading status in the final notes.
Sources
- Python 3.15.0rc2 (September 1, 2026)python.org
- Python 3.15.0rc3 (October 2, 2026)python.org
- What's New in Python 3.15docs.python.org
Provenance
The note above is reproduced unedited from the original post, first published on Threads on 22 September 2026 at 01:32 IST. Sources are the papers and datasets the note draws on.
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