Python 3.15.0 Beta 3 Released
Python 3.15.0 beta 3 is available as a preview of the upcoming Python 3.15 release, offering bug fixes and build improvements. This release is intended for wider community testing to prepare projects for the new features. Maintainers are encouraged to test their projects and report issues, but production use is not recommended until the release candidate phase.
- →New Features Introduced in Python 3.15
- →Removals and New Deprecations in Python 3.15
- →Performance Improvements and Interpreter Updates
- →C API and ABI Enhancements
- →Beta Testing Encouraged for Third-Party Projects
Deprecations (1) ›
- Removals and New Deprecations in Python 3.15
This beta release also includes information on upcoming removals and new deprecations within Python 3.15, covering both the language and its C API. An overview of pending deprecations is also available.
Features (1) ›
- New Features Introduced in Python 3.15
Python 3.15 introduces several new features including PEP 810 for explicit lazy imports, PEP 814 for a built-in frozendict type, and PEP 661 for a built-in sentinel type. Other enhancements include a dedicated profiling package (PEP 799), enabled frame pointers by default, unpacking in comprehensions, UTF-8 as the default encoding, and package startup configuration files.
Enhancements (2) ›
- Performance Improvements and Interpreter Updates
The JIT compiler has been upgraded, providing performance improvements on x86-64 Linux and AArch64 macOS. The official Windows 64-bit binaries now utilize the tail-calling interpreter, and error messages and color output have been improved.
- C API and ABI Enhancements
Python 3.15 includes updates to the C API, such as PEP 782 for PyBytesWriter and PEP 803, 820, 793 for a stable ABI for free-threaded builds. These changes aim to improve compatibility and performance for C extensions.
Notes (2) ›
- Beta Testing Encouraged for Third-Party Projects
Maintainers of third-party Python projects are strongly encouraged to test their projects with Python 3.15.0b3 to identify and report any issues. Creating pre-release wheels for 3.15 is recommended to facilitate this testing process.
- Release Schedule and Support
Python 3.15.0 beta 4 is scheduled for 2026-07-18, with the release candidate phase starting on 2026-08-04. Production use is advised to wait until the first release candidate to avoid potential ABI breaks.
https://blog.python.org/2026/06/python-3150-beta-3/