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) :)
Keep in mind that once you commit the upgrade to the team server, you can't go back. I recommend you create a copy of the project on your local development machine, open it up in the new modeler, test the widgets and the attempt to build and run the project after clearing all of your errors. Look closely at any custom widget uses or JavaScript/Java action references to ensure they still work. If so commit to the team server and move forward. If not, delete it and use your original file until you work out what is holding you back. Also I recommend you don't jump early to upgrade unless there is a feature in the release notes that are a must have. Hope that helps.