The most important difference is that the upgrade license has to be attached to the original base license.
- If your original base license is a full retail Windows 11 Home license, then it becomes a full retail Windows 11 Pro license. This is a transferable license to another computer.
- If your original base license is an OEM Windows 11 Home license, then it becomes an OEM Windows 11 Pro license. This is a non-transferable license.