after downgrading my Vera3 to UI5 for the last few years, I think I’m ready to give UI7 another try, was wondering if I need to buy PLEG licenses again?
I think it is possible to request richard to move the license from your old device I might be wrong but you can ask.
Anyhow since the prize of the plugin is in the range of 1 beer in a bar why don’t you just buy the author another beer for his effort 
If you migrate from UI5 to UI7 on the same device you do not need a new license.
If you move from one Vera Device to another Vera Device you will need a new license. The license is tied to the Vera Serial Number.
I do have an upgrade policy … but it only saves money if you have more than 1 license.
My upgrade process is:
If you have N licenses … they you purchase RoundUpToNearestInteger(N/3) liceneses and I provide the remainder.
So if N =1 you still need to buy one license.