• Tuesday, January 13, 2026 Python 3.15.0 alpha 4 This is an early developer preview of Python 3.15 www.python.org/downloads/release/python-3150a4/ Major new features of the 3.15 series, compared to 3.14 Python 3.15 is still in development. • This release, 3.15.0a4, is the fourth of seven planned alpha releases. • Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process. • During the alpha phase, features may be added up until the start of the beta phase (2026-05-05) and, if necessary, may be modified or deleted up until the release candidate phase (2026-07-28). • Please keep in mind that this is a preview release and its use isnotrecommended for production environments. • Many new features for Python 3.15 are still being planned and written.

Article Summaries:

  • Python 3.15.0 a4, the fourth of seven planned alpha releases, has been released as an early developer preview. The release introduces several major features, including PEP 799’s high‑frequency statistical profiler, PEP 686’s default UTF‑8 encoding, and a new PyBytesWriter C API (PEP 782). A significant JIT upgrade delivers 3‑4 % performance gains on x86‑64 Linux and 7‑8 % on AArch64 macOS. Additional improvements cover error messages and other minor changes. The alpha phase will continue until the beta launch on 5 May 2026, with a release candidate slated for 28 July 2026. The next pre‑release, 3.15.0 a5, is scheduled for 10 Feb 2026.
  • Python’s core team released Python 3.15.0a5, the fifth of seven planned alpha builds for the upcoming 3.15 series. The update corrects an earlier build that was mistakenly compiled against a 2025‑12‑23 snapshot, now using the 2026‑01‑14 baseline. Alpha releases are intended for testing new features and the release process; they are not recommended for production use. Key highlights include PEP 799’s statistical profiler, PEP 686’s default UTF‑8 encoding, PEP 782’s new bytes‑writer API, and a JIT upgrade delivering 4‑5 % speed gains on x86‑64 Linux and 7‑8 % on AArch64 macOS. The next alpha, 3.15.0a6, is slated for 2026‑02‑10.

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