Semver 3.0.0-dev.2 – Semantic Versioning

If you are searching for how to stay compatible with semver3, refer to Migrating from semver2 to semver3.


This is a development version. Do NOT use it in production before the final 3.0.0 is released.


A Python module for semantic versioning. Simplifies comparing versions.

Python Python versions Monthly downloads from PyPI Software license Documentation Status Black Formatter Percentage of open issues GitHub Discussion


This project works for Python 3.6 and greater only. If you are looking for a compatible version for Python 2, use the maintenance branch maint/v2.

The last version of semver which supports Python 2.7 to 3.5 will be 2.x.y However, keep in mind, the major 2 release is frozen: no new features nor backports will be integrated.

We recommend to upgrade your workflow to Python 3.x to gain support, bugfixes, and new features.

The module follows the MAJOR.MINOR.PATCH style:

  • MAJOR version when you make incompatible API changes,

  • MINOR version when you add functionality in a backwards compatible manner, and

  • PATCH version when you make backwards compatible bug fixes.

Additional labels for pre-release and build metadata are supported.

To import this library, use:

>>> import semver

Working with the library is quite straightforward. To turn a version string into the different parts, use the semver.Version.parse function:

>>> ver = semver.Version.parse('1.2.3-pre.2+build.4')
>>> ver.major
>>> ver.minor
>>> ver.patch
>>> ver.prerelease

To raise parts of a version, there are a couple of functions available for you. The function semver.Version.bump_major leaves the original object untouched, but returns a new semver.Version instance with the raised major part:

>>> ver = semver.Version.parse("3.4.5")
>>> ver.bump_major()
Version(major=4, minor=0, patch=0, prerelease=None, build=None)

It is allowed to concatenate different “bump functions”:

>>> ver.bump_major().bump_minor()
Version(major=4, minor=1, patch=0, prerelease=None, build=None)

To compare two versions, semver provides the function. The return value indicates the relationship between the first and second version:

>>>"1.0.0", "2.0.0")
>>>"2.0.0", "1.0.0")
>>>"2.0.0", "2.0.0")

There are other functions to discover. Read on!

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