Plan for dropping Python 2.7 support

The Python core team plans to stop supporting Python 2 in 2020. The NumPy project has supported both Python 2 and Python 3 in parallel since 2010, and has found that supporting Python 2 is an increasing burden on our limited resources; thus, we plan to eventually drop Python 2 support as well. Now that we’re entering the final years of community-supported Python 2, the NumPy project wants to clarify our plans, with the goal of to helping our downstream ecosystem make plans and accomplish the transition with as little disruption as possible.

Our current plan is as follows.

Until December 31, 2018, all NumPy releases will fully support both Python2 and Python3.

Starting on January 1, 2019, any new feature releases will support only Python3.

The last Python2 supporting release will be designated as a long term support (LTS) release, meaning that we will continue to merge bug fixes and make bug fix releases for a longer period than usual. Specifically, it will be supported by the community until December 31, 2019.

On January 1, 2020 we will raise a toast to Python2, and community support for the last Python2 supporting release will come to an end. However, it will continue to be available on PyPI indefinitely, and if any commercial vendors wish to extend the LTS support past this point then we are open to letting them use the LTS branch in the official NumPy repository to coordinate that.

If you are a NumPy user who requires ongoing Python2 support in 2020 or later, then please contact your vendor. If you are a vendor who wishes to continue to support NumPy on Python2 in 2020+, please get in touch; ideally we’d like you to get involved in maintaining the LTS before it actually hits end of life so that we can make a clean handoff.

To minimize disruption, running pip install numpy on Python 2 will continue to give the last working release in perpetuity, but after January 1, 2019 it may not contain the latest features, and after January 1, 2020 it may not contain the latest bug fixes.

For more information on the scientific Python ecosystem’s transition to Python3 only, see the python3-statement.

For more information on porting your code to run on Python 3, see the python3-howto.