You can easily check for the latest published version of CMigrator by visiting https://compojoom.com, logging into the site and going to Downloads->CMigrator (you need a valid subscription).
Updating CMigrator to the latest version is by no means different than installing the component! You do not have to uninstall the previous version; in fact, you are discouraged from doing so. Simply follow the installation instructions so as to install the latest CMigrator version over the existing CMigrator installation. That's all! All your settings are preserved.