Instructions for updating ILIAS can be found in section 3 of the general installation instructions. For major updates (e.g. 4.4.x -> 5.0.x) the safest proceeding is, to upgrade a copy of your productive system first and test whether everything works ok.

If you use a customized skin/style, please change the skin settings for root user and default of installation to ‘delos‘ before upgrading from a 4.x version to 5.2.x. Otherwise you may not login any more due to templates changes in former versions.

ILIAS is free, open source software and published under the GNU General Public License (GPL).