For the portable Windows version, extract the latest version on top of your old folder. To update an existing installation, simply run the latest installer (for Windows) or replace the old app in your Applications folder (for Mac). If you do not have Internet access during installation, you can pre-install the runtime from Microsoft's website or use the portable version. The Windows installer package may require an Internet connection to download the latest Microsoft Visual C++ Runtime if your PC does not already have it installed.
