PLIP: drop Python 3.8 and 3.9 in Plone 6.1

[mauritsvanrees]

Responsible Persons

Proposer: Maurits van Rees

Seconder:

Abstract

As agreed in the Plone Steering on 2024-03-07, let's drop Python 3.8 and 3.9 support in Plone 6.1. See community announcement that I just made.

It has already been decided. But in a discussion during the German Plone Tagung last week, we saw value in having a PLIP for all such major changes, even when it is a PLIP after the fact.

Motivation

Until now, the alpha releases of Plone 6.1 supported five Python versions: 3.8 through 3.12. In the next alpha we will drop 3.8 and 3.9. So 6.1 will support 3.10, 3.11, and 3.12. This was agreed during the meeting of the Plone Steering Circle last week. This is a meeting of Plone team leaders.

This means less burden on maintainers within the Plone community, like the release team and A/I team (including testing), and opens up the possibility for Plone core developers to use some more recent features. For inspiration, here is the Python document explaining what is new in each Python version:
https://docs.python.org/3/whatsnew/index.html

See what's new in 3.9 and 3.10 for what we can now use in 6.1 that was not possible earlier, for example the zoneinfo module and structural pattern matching (match/case).

Assumptions

If you must use an older Python version, you can stay on Plone 6.0, which will support each Python version until it runs out of security support from the Python community. For Python 3.8 this is October 2024, for Python 3.9 this is October 2025. See https://www.python.org/downloads/.

Proposal & Implementation

The only thing we really must do is announce it, and make it clear in the release notes and update the release schedule.

Deliverables

• Announce it: https://community.plone.org/t/python-6-1-will-drop-support-for-python-3-8-and-3-9/19128?u=mauritsvanrees
• Update release schedule: https://plone.org/download/release-schedule
• Update Jenkins to no longer run 3.8 and 3.9 jobs for 6.1: Plone 6.1: drop jobs for Python 3.8 and 3.9 jenkins.plone.org#353
• Update mr.roboto as well probably.
• Drop 3.8 and 3.9 classifiers from packages that are for 6.1 only.
• Add python_requires>=3.10 to at least Plone and Products.CMFPlone. We could also wait until there is a change that really requires a newer Python version.
• Add this to the upgrade guide for 6.1.

Perhaps:

• Check if changes in plone/meta are needed for packages that only run on 6.1.

Risks

This will break for users that currently have a 6.1 alpha site on 3.8 or 3.9. But that seems unlikely: I expect all 6.1 users to use at least 3.11.

Participants

• Maurits van Rees