You can download and install the latest modeler. You then have multiple versions on your pc. That’s the way to do it.
Go to the App Store, then select the modeller section, download the newest, open the modeller wioth your project.
If you are the first user who is updating, you will get an question if you want to migrate your project to a newer version. If you accept it, your local project will be migrated. If you have migrated and you have non svn version project, you are not able to get back to an lower version. If you have svn project, you can test your application with the new modeller. If you ant to keep the version, do an commit.
If you are the second person and you get the information by opening your svn based project that a new modeller is based, you only need to download the modeller. By opening, you will get a question to migrate your local project, you need to accept it. After that you can do an update.