“By upgrading to the full version, you will gain access to additional features and receive technical support.”
You could also consider these alternatives depending on your tone: “By upgrading to the full version, you will
“Go full version – unlock all features and enjoy technical support.” “By upgrading to the full version
“Upgrade to the full version to access more features and receive technical support.” suitable for a pop-up
Here’s a polished version of that sentence, suitable for a pop-up, banner, or settings screen: