Users are very confused and worried any time a new version of wiki software is launched and tested, and some major or minor bug comes invariably out.
A clear message using central sitenotice, with links to doc pages listing the changes at different levels of detail and to their talk pages to discuss them and to alert for bugs, is mandatory IMHO. Tech news are largely insufficient; evidence of work in progress should be clearly visible into all pages of interested projects. It's a basic matter of Wikilove.
Alex