Python 3.12 Release Notes

Release Date: October 2, 2023

Python 3.12 is a stable release focused on improvements in typing, performance, and language usability.

What's New in Python 3.12

Performance Improvements

• CPython optimizations and reduced memory usage:
  • Removal of legacy internal Unicode fields (wstr).
• Faster operations:
  • re.sub() up to ~2–3x faster in some cases.
  • Faster asyncio.Task creation.
• Experimental support for the BOLT optimizer.
• General performance improvements across the standard library. :contentReference[oaicite:8]{index=8}

Language Changes

• PEP 695: New type parameter syntax:

  • More concise generics.
  • New type statement for type aliases. :contentReference[oaicite:9]{index=9}

• PEP 701: Formalized f-strings:

  • Support for multiline expressions, comments, and more flexible syntax. :contentReference[oaicite:10]{index=10}

• Improved error messages:

  • Better suggestions and diagnostics. :contentReference[oaicite:11]{index=11}

Interpreter and Runtime

• PEP 669: Low-impact monitoring API:

  • Near-zero overhead profiling and debugging tools. :contentReference[oaicite:12]{index=12}

• PEP 684: Per-interpreter GIL:

  • Better isolation and scalability for multi-interpreter setups.

• Linux perf profiler integration.

Typing

• PEP 692: Precise **kwargs typing with TypedDict.
• PEP 698: typing.override decorator.
• Improved typing ergonomics. :contentReference[oaicite:13]{index=13}

Standard Library

• Improvements in asyncio (performance and features).
• Enhancements to os, pathlib, and other modules.
• PEP 688: Buffer protocol accessible from Python. :contentReference[oaicite:14]{index=14}

Removals and Deprecations

• Removal of distutils from the standard library. :contentReference[oaicite:15]{index=15}
• Cleanup of deprecated APIs and legacy features.

Internals

• CPython bytecode changes:
  • Simplified and optimized instruction set.
• Improvements to C API and internal structures.

Migration Notes

When upgrading from Python 3.11:

• Replace distutils with setuptools.
• Review deprecated and removed APIs.
• Update typing-related code where needed.
• Test third-party dependencies.

Documentation

Official 3.12 documentation