Updating
If there are no notes in the changelog of the latest version, it is enough to extract the directories Themes
and Sources
from the modification archive to the root of your forum, over the existing ones, and the update will be correct. But it's best to uninstall the current version before installing the new version.
Note
If the new version can be installed without removing the previous one, you'll see the "Upgrade" button instead of the "Install" button: