META: LNH or LNH20?

[Michael D Friedman]

So, I've been trying to research things, but there's just a ton of stuff out there and I've been gone for over a decade, so... Can somebody explain the division of LNH and LNH20 for me? 

Is LNH20 just a universe for rebooting the LNH, or are there specific fundamental differences between the two? I was noticing in some previous discussions when the LNH20 idea was being discussed, something about ownership rights, etc. Is there a specific historical "reboot" model that the LNH20 stories all relate to? (Like, all characters rebooted due to X event).

For example, let's say that theoretically a certain author were to write a theoretical one-shot story, theoretically rebooting his main LNH creation, would that author automatically set this series in LNH20, since it's a reboot? Or theoretically, would this still exist in LNH, since it wasn't developed as a LNH20 story (with whatever theoretical history that may theoretically have)? This is all theoretical, mind you.

Thanks.

- Mike.