Charmcraft 4.2 release notes¶
17 March 2026
Learn about the new features, changes, and fixes introduced in Charmcraft 4.2.
Requirements and compatibility¶
For development and testing, Charmcraft requires a host with a minimum of 4GB RAM running a Linux distribution compatible with systemd.
All versions of Charmcraft require the following software:
We recommend you install the Charmcraft snap. It comes bundled with all its dependencies.
Non-snap installations of Charmcraft have the following dependencies:
What’s new¶
Charmcraft 4.2 brings the following new features.
Init template updates¶
Charmcraft 4.2 sets Ubuntu 24.04 as the default base for new charms using the machine, kubernetes, django-framework and flask-framework init templates.
The machine and kubernetes templates also now assume Juju 3.6 or newer.
Faster startup for new charms or after cleaning¶
When installed as a snap, Charmcraft now also injects the core24 snap into the created container from the host machine, speeding up initial builds and reducing the download time.
Compiled bytecode from the uv plugin¶
The uv plugin now compiles bytecode for installed Python files
by default. To disable this for your charm, set UV_COMPILE_BYTECODE: false in
the part’s build-environment key.
Documentation improvements¶
Across the documentation, we made numerous technical corrections, fixed many links, and revised the formatting. We also added:
Known issues¶
The following issues were reported and are scheduled to be fixed in upcoming patch releases.
See individual issue links for any mitigations.
Contributors¶
We would like to express a big thank you to all the people who contributed to this release:
@activus-d,
@alithethird,
@arturo-seijas,
@bepri,
@dwilding,
@f-atwi,
@jahn-junior,
@james-garner-canonical,
@javierdelapuente,
@jonathan-conder,
@lengau,
@medubelko,
@mr-cal,
@smethnani,
@tigarmo,
@tonyandrewmeyer,
and @zhijie-yang