@Cattext: All free themes that are hosted in WordPress.org get update automatic like that. But for Premium and Pro version, you need to update it manually using WordPress Theme Uploader or FTP. You can check in our theme instructions page at http://catchthemes.com/theme-instructions/catch-kathmandu-pro/
First, I recommend you to install Catch Updater plugin. This is one time installation and after that you don’t need to do again and again. Just download plugin from http://catchthemes.com/wp-plugins/catch-updater/ and install plugin from “Plugins => Add New => Uploads”
Then finally, you can download the latest version of Catch Kathmandu Pro from your account at http://catchthemes.com/my-account and then upload it from “Appearance => Themes => Add New => Uploads”