Generally, Discourse has been kept up-to-date using its automated systems. This week however, we have upgraded the underlying base system to the latest OS. This required a full backup and restore of the Discourse data. Existing sessions may have been logged out.
The old system is still available to us, though not to the wider web. If you are having issues with Discourse after this upgrade, please leave a note so we may investigate. The old system will be decommissioned in a week (though backups from before the changeover remain if necessary.)
If you are now unable to access Discourse, please contact us on our Gitter or the #matplotlib channel on the Scientific Python discord.