It's strongly recommended that you make a backup of your DomainMOD installation directory and database before upgrading. If something goes wrong during the upgrade there may be no way to recover your data, and having a backup of your installation directory and database will allow you to restore your previous installation.
If you installed DomainMOD by downloading the .ZIP file, visit the following URL to download the most up-to-date version: https://domainmod.org/download/
Once the download completes, upload and unpack the new archive overtop of where you installed the previous version (or unpack it and then upload it, whichever you prefer).
If you installed DomainMOD using git right from your web server, just run the following command from within your installation directory to upgrade:
If you installed DomainMOD using Softaculous you're just a few clicks away from upgrading to the newest version. Please see the upgrade instructions on the Softaculous Wiki: https://www.softaculous.com/docs/How_to_upgrade_installations