Hi,
As the subject line hints, we're doing something a little different with this release. There was a lot of work done on MW-CS over the summer by our GSoC student, Lethexie.
There are a significant number of changes, especially to do with documentation comments. So we are releasing this as alpha quality to ask for more feedback on the changes to the ruleset. You can upgrade in the same manner as normal - by updating the version number in the composer.json file.
Feel free to provide feedback by responding to this thread or by filing a bug in the MediaWiki-Codesniffer Phabricator project. We would like to release 0.8.0 by mid-October.
Thanks! -- Legoktm