Hello ,
At this time, there is no cost for current commercial licensees to upgrade to the Twinmotion 2023.1 version, regardless of license purchase date. You can use Twinmotion 2023.1 Preview 1, which will update to final 2023.1 version once that becomes available, at no cost.
For future reference, any version of Twinmotion found in the dropdown list of the Twinmotion page in the Epic Games Launcher is available with your license. You can download these whenever you need on any computer at no additional cost.
Best,
Raghib