Read the official Contao announcements.
TYPOlight 2.1 is available
by Leo Feyer
TYPOlight 2.1 is available for download. It introduces a powerful live update feature that allows to update your installation online with only a few clicks! Thus you can get important patches as soon as they have been released. You do not have to download any files or use an FTP client to update your system anymore. If you are updating from version 2.0, there is a special update package that includes modified files only. Take a look at the changelog to see what has been done.
Download this release from github.com.