Well I'm amazed how this plugin works flawlessly! I have modified it and now using just serializing license using json. On the clients I always have base model of license (fields that always must exist) and just ignore missing members. Therefore any changes to license do not affect old clients.
So I can change licensing key model as I want and nothing is broken.
I'm trying to install the 3.70 version, but afther adding the project to the plugins folder, whenever i build the solution it says i'm missing packages, even afther ensuring every package has been updated in the nuget package manager regarding this particular plugin.