.python Version Fixed Jun 2026

A .python-version file is a plain-text configuration file placed in the root directory of a project. It contains exactly one piece of information: 3.11.4 Use code with caution.

The primary user runtime configuration file (e.g., ~/.pyenv/version or Windows py.ini ) System Default

The version listed in .python-version isn’t installed in pyenv .

Setting up a project-specific version file is straightforward. Using pyenv (Recommended)

in 3.13/3.14 have focused heavily on closing the performance gap with other languages [10, 38]. Modern Features : Recent versions have added powerful syntax like (3.6), the walrus operator (3.8), and structural pattern matching (3.10) [5, 37]. Python Version Support Roadmap .python version

curl https://pyenv.run | bash

You can create this file manually or via command line tools: : Create a file named .python-version (or your preferred version) inside. Command Line pyenv local 3.12.0 will automatically generate or update the .python-version file in your current folder. like pyenv to start using these files?

try , except , raise , finally (managing errors).

Newer versions (e.g., 3.11+) are significantly faster. Python Version Support Roadmap curl https://pyenv

Several ecosystem-standard tools recognize and respect the .python-version file:

The .python-version file handles the , whereas tools like virtual environments ( venv ) handle the installed library dependencies (like NumPy, Django, or Flask). For optimal workflows, developers use a .python-version file to control the binary engine, which then generates a tightly scoped virtual environment for packages. Best Practices for Teams and Version Control

If a teammate pulls your repository and runs a command, they might see an error stating that the version specified in .python-version is missing. They simply need to run the install command for their respective tool (e.g., pyenv install without arguments will often read the file and install the missing version automatically).

When placed in the root of your project, tools like pyenv automatically switch to that version whenever you cd into the folder. 15]. Python 3.15

Despite its simplicity, .python-version supports several useful syntax patterns:

In modern development, different projects often require different versions of Python. For example, a legacy application might run on Python 3.8, while a new project leverages features from Python 3.12. Manually switching versions is error-prone and tedious. The .python-version file solves this by:

over version 3.10 through the "Faster CPython" project [13, 15]. Python 3.15