If you are using a version older than OTRS::ITSM 1.1, please update the system to the latest version 1.1 first.
If OTRS::ITSM 1.1 has already been installed, update your OTRS 2.2 framework to version 2.3 BEFORE you update OTRS:ITSM. To do so, download the latest OTRS 2.3 framework and follow the instructions in the file named UPGRADING. After that, log in to your system and use the package manager to install the package ITSMUpgradeTo12. You can download it manually or use the online repository. Ignore all error messages about not correctly installed old ITSM packages. This package will install all needed packages to update your system to an OTRS::ITSM 1.2 version, and it will migrate all of your data.
Note: The upgrade can take several minutes! Please do not stop the upgrade process once it is running!
If OTRS::ITSM 1.2 is already installed, update your OTRS 2.3 framework to version 2.4 BEFORE you update OTRS:ITSM. To do so, download the latest OTRS 2.4 framework and follow the instructions in the file UPGRADING. After that, log in to your system and use the package manager to install the packages as described in the section "Installation".
To upgrade an already installed OTRS::ITSM 1.3, use the package manager in the admin area. If you have internet access from OTRS, use the online repository [--OTRS::ITSM 1.3 Master--] to install newer packages. An 'upgrade' link next to the package name indicates if a newer package is available.
Otherwise, download the packages and use the package manager to install the packages. WARNING: Do not uninstall your current packages, or you will lose data!