The Python Software Foundation has released Python 3.15.0 as the stable version, according to its download page. It says the release holds 5,643 commits from 1,012 contributors. Python now reads and writes text as UTF-8 by default. Modules can also be imported lazily, so they load only on first use. A sampling profiler called Tachyon, which checks a running program at intervals to find slow code, is included. The foundation says its experimental JIT compiler, which turns code into machine code as the program runs, is 7-8% faster on average on x86-64 Linux. Developer Simon Willison wrote on 12 October that Python 3.10 is now officially unsupported.
The foundation warns that IDLE and other apps built on tkinter may freeze on macOS 27.0 when they open a dialog box. It believes the change in macOS affects all current versions of the Tk toolkit, and so all current Python versions. No fix exists yet, and it points readers to issue #158053. The page gives no release date. Miguel Grinberg tested release candidate 3 and found speed mostly the same as 3.14, except for the JIT. It ran a Fibonacci test 1.2 times faster, he found, as Willison reported. The sources do not show how that result compares with the foundation's figures.
Teams that follow Python's support window can now drop 3.10 and rely on 3.11 features. Willison says he plans to do so across his open source projects. Anyone who ships Tk-based tools on Macs has a reason to test before moving to macOS 27.0, the foundation says.