For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest.
Your licensed install file is likely available in this folder on the PC: "C:\Program Files (x86)\NCH Software\VideoPad"
If not, mention the desired version here and someone will point you to a downloadable file.
Once installed, just register as before if necessary.
https://www.nch.com.au/upgrade/