Update to supervisor 4.0.0 or later for Python 3 support

[redshiftzero]

The version of supervisor currently packaged here is compliant only with Python 2. Since Python 2 will EOL in a few months (January 1, 2020), it would be good to update to a version of supervisor that is based on Python 3. The first supervisor version on PyPI that supports Python 3 is 4.0.0: https://github.com/Supervisor/supervisor/issues/1060#issuecomment-480438643, so it would be nice to update to at least 4.0.0 or later.

[Hans Joachim Desserud (hjd)]

Thanks for reporting.

I see that supervisor 4.0.4-2 has been packaged in Debian (https://tracker.debian.org/pkg/supervisor). Looks like it was a bit too late for the 19.10 release, but this should be synced automatically for the Ubuntu 20.04 archives soon.

[redshiftzero (redshiftzero)]

Ah great! Will that updated package not be included in the 16.04 and 18.04 LTSes also? I'm asking because the 16.04 and 18.04 LTS would then be continuing to use this Python 2 only based version, which seems problematic from a security standpoint once Python 2 EOLs.

[Hans Joachim Desserud (hjd)]

I don't think it will be automatically added to older releases, but it is always possible to request a backport, see https://wiki.ubuntu.com/UbuntuBackports#Requesting_a_Backport

>seems problematic from a security standpoint once Python 2 EOLs.

There is a lot of other packages which also depend on Python2 and the LTS releases are supported for 5 years. So while I don't know the exact plans, I would assume Ubuntu/Canonical will keep patching Python2 in the LTS releases when/if security issues are discovered. :)

[Hans Joachim Desserud (hjd)]

supervisor 4.1.0-1ubuntu1 has been synced to Ubuntu Focal, so that covers the upcoming 20.04 LTS at least (https://bugs.launchpad.net/ubuntu/+source/supervisor/4.1.0-1ubuntu1)