The XOOPS Upgrader examines your XOOPS installation and applies any needed patches to make it compatible with the new XOOPS code. Patches may include database changes, adding default settings for new configuration items, file and data updates, and more.
The upgrader is tested against a variety of XOOPS installation, both old and new, but the process is smoothest with the most recent XOOPS releases. If you are upgrading a older system and need help, please visit our support forums at https://xoops.org/modules/newbb/
Make a full backup of site files and database
It may be helpful to enable debugging in System Options - Preferences - General Settings
It is wise to turn your site off in System Options - Preferences - General Settings
Copy the contents of the distribution htdocs directory into your web root directory. Be careful not to overwrite any customize configuration or theme files.
Copy the contents of htdocs/xoops_lib to your relocated/renamed xoops_lib as applicable
Copy the contents of htdocs/xoops_data to your relocated/renamed xoops_data as applicable
If you are upgrading from a pre-2.5 series XOOPS, check your mainfile.php for any old protector modifications and remove if found
Copy the distribution upgrade directory into your web root directory
Point your browser to your-site-url/upgrade/ and follow the prompts
Log in and step through any needed updates with the "Continue" button
At the end, upgrade the system module
Also update pm, profile and protector modules if installed