Python 313 Release Notes Verified «Latest»

The garbage collector has been reworked to be . Previously, full GC cycles could cause noticeable "stop-the-world" pauses, especially in applications with many objects.

The performance picture for Python 3.13 is nuanced. The free-threaded mode unlocks true concurrency for CPU-bound tasks but penalizes single-threaded performance. The JIT compiler is a promising foundation that does not yet deliver significant speedups. However, for typical single-threaded workflows, Python 3.13 is largely on par with or slightly faster than Python 3.12 for many tasks, with specific improvements seen in simple list comprehensions.

: It relies on a modified version of Microsoft's mimalloc memory allocator to ensure thread safety without the heavy bottleneck of a global lock. Copy-and-Patch JIT Compiler (PEP 744)

If you attempt to import a sub-module that does not exist but a similarly named module does, the error clearly points out the typo. 5. Typing and Language Syntax Upgrades python 313 release notes verified

Note: Python 3.13.0 has been superseded by Python 3.13.13. Release date: Oct. 7, 2024. Python.org Python Release Python 3.13.13

Python 3.13 is a significant milestone release focusing on the future architecture of the language (JIT and Free-Threading). However, because these major features are experimental, 3.13 is considered a "transitional" release. It is safe for general use, but developers should strictly test their code against the new REPL and warnings regarding escape sequences.

Typing help directly in the REPL is more intuitive. 4. Significant Library and Language Changes The garbage collector has been reworked to be

Verified: GC now runs on a separate thread (when free-threaded). Reality: This reduces stop-the-world pauses in multi-threaded apps. For most single-threaded scripts, you won't notice. For async servers or GUI apps, responsiveness improves.

The community has been actively testing and verifying these claims. Projects like "gil-vs-no-gil" on GitHub provide reproducible frameworks for developers to benchmark Python 3.13 (with GIL) against Python 3.13t (without GIL), demonstrating the clear performance benefits for multi-threaded, CPU-intensive code when the GIL is removed.

How to try it:

python3.12 -Wd your_application.py

from typing import Generic, TypeVar T = TypeVar("T", default=str) class Box(Generic[T]): def __init__(self, content: T): self.content = content # Defaults to Box[str] default_box = Box("Hello") Use code with caution. The @deprecated Decorator (PEP 702)

Python 3.13 was officially released on October 7, 2024 . This major update introduces foundational changes to Python's performance and developer experience, most notably the experimental "free-threaded" mode and a Just-In-Time (JIT) compiler. Key Verified Release Highlights Experimental Free-Threaded Mode (PEP 703) : It relies on a modified version of

The CPython C API has undergone significant changes in 3.13:

, released on April 7, 2026. Regular bugfix updates with binary installers are scheduled through October 2026, after which it will receive security updates only until October 2029. What's New In Python 3.13 — Python 3.14.4 documentation