Uninstall version and go back to prior version

I’m wondering if it is possible to go back to a prior version of Piwik. What is the best way to uninstall current version and go back to the version before? Does anyone know how to do this safely?

After installing 3.01 some function does not work:
exporting reports more than 100 rows
e-mail reports (gives warning messages)
making a report flat does not include all rows so some statistics are missing.

Maybe the Piwik team is working on a fix to solve all these problems, but if not we will have to go back to an earlier version when it worked.

Best regards,