• The browser plugin now has a new page with information about your sabredav
  server, and shows information about every plugin that's loaded in the
  system.
• #191: The Authentication system can now support multiple authentication
  backends.
• Removed: all $tableName arguments from every PDO backend. This was already
  deprecated, but has now been fully removed. All of these have been replaced
  with public properties.
• Deleted several classes that were already deprecated much earlier:
  • Sabre\CalDAV\CalendarRootNode
  • Sabre\CalDAV\UserCalendars
  • Sabre\DAV\Exception\FileNotFound
  • Sabre\DAV\Locks\Backend\FS
  • Sabre\DAV\PartialUpdate\IFile
  • Sabre\DAV\URLUtil
• Removed: Sabre\DAV\Client::addTrustedCertificates and
  Sabre\DAV\Client::setVerifyPeer.
• Removed: Sabre\DAV\Plugin::getPlugin() can now no longer return plugins
  based on its class name.
• Removed: Sabre\DAVACL\Plugin::getPrincipalByEmail().
• #560: GuessContentType plugin will now set content-type to
  application/octet-stream if a better content-type could not be determined.
• #568: Added a componentType argument to ICSExportPlugin, allowing you to
  specifically fetch VEVENT, VTODO or VJOURNAL.
• #582: Authentication backend interface changed to be stateless. If you
  implemented your own authentication backend, make sure you upgrade your class
  to the latest API!
• #582: Sabre\DAV\Auth\Plugin::getCurrentUser() is now deprecated. Use
  Sabre\DAV\Auth\Plugin::getCurrentPrincipal() instead.