Answer

Click on the “Update Available” at the bottom of XSplit Gamecaster’s main screen and then click on “Update now” to automatically update to the latest version of XSplit Gamecaster.
You can also visit XSplit Gamecaster’s website to download the latest version of XSplit Gamecaster. (https://www.xsplit.com/download)

*If you haven’t redeemed the MSI exclusive 6 months free premium license, find the guide at the below FAQ link. (http://www.msi.com/faq/nb-1198.html)

Reference