To upgrade existing Geneious installations, simply download and install the new version to the same location. Your existing data and license will be automatically loaded in the new version. If you are upgrading to a new major version (e.g. 11.1 to Prime 2019.0, or Prime 2019.0 to 2019.1). Geneious will update your data folder to the new format (creating a new folder with the upgrade’s version number in the name), and will offer to keep a copy of your old data folder in case you wish to downgrade.
In Geneious Prime 2021 onwards, updates will automatically download when available to your data directory and you will be prompted to install the newest version of Geneious Prime when it is available.