I assume you want to know how to update a project which is currently in 6.10.0?
You can download the 6.10.4 version of the modeler and install it. Then when you start the modeler choose 'Open app' and select 'Disk'. Now you can open your app, which was made in a previous version, and convert it in place to upgrade the project to 6.10.4.
Check https://docs.mendix.com/releasenotes/desktop-modeler/6.10 and hit the download button (or direct link) :)