Login as the Super User in Piwik, go to Settings > General Settings. Next to “When checking for new version of Piwik, always get”, select “The latest beta release”. Click Save at the bottom of the page. You are now using the beta release channel!
If you want to update to the latest beta version, go to Settings, then click on the “Check for updates” box in the top right of the screen. In this box, click “Check for updates”. If a new beta is available, the “About Piwik” box will turn orange. You can then update Piwik in one click.
Thank you for using the beta channel and for your time reporting any bug you may experience.