Release 5.0.0 has been published on 6th February 2015.
Please read the ILIAS 5 features report for information about major changes and new features of this version.
Information about first time installation can be found here.
Before upgrading an ILIAS installation of version 3.9 or lower to 5.0 you will need to upgrade to 3.10 first. Instructions for updating ILIAS can be found in section 3 of the general installation instructions. For major updates (e.g. 4.3.x -> 4.4.x) the safest proceeding is, to upgrade a copy of your productive system first and test whether everything works ok.
If your ILIAS uses a customised skin / style, please change the skin of your root (or admin) user to the default ILIAS / Delos before updating to 5.0. Otherwise you might have problems to access ILIAS after the update due to several UI changes related to the design revision of ILIAS 5.0.
99% of our almost 1500 test cases have run successfully. All component maintainers have given their "Go" to publish ILIAS 5.0.0. as a stable release. Please note that the ECS component is not included in the current test scenarios and has not been fully tested yet. For other open issues, please visit out bug tracker.