So we've been using OPAC on a large server for over a year now and whilst the protection part of the mod has been really good with extensive Create support the configuration aspect has been very tedious and confusing for new players.

To try and improve on this I want to work on a mod that tries to simplify some of OPACs mechanics using custom block and item interactions in a seperate addon mod. Essentially it would act like a wrapper with OPAC staying as a required dependency for the project.

My only problem is whilst OPAC is currently licensed under LGPL-3.0-only you say that this license may change in the future.
This type of mod needs to use Mixins to disable certain functionality like claiming land using a map or with commands (for non admins) so if you ever decided to change to a more restrictive license I would likely have to drop support entirely. Especially if you switch to a private repository.

I'm really excited about this project but ultimately if there is no guarentee of a fixed license then I likely can't use OPAC as a dependency and i'll have to go with another claims mod that has a fixed and open license like Cadmus.

People who downloaded the mod or the source code under LGPL-3.0-only will not ever lose that license retroactively. I'm talking about theoretical future releases. Even if for some crazy reason I decide to go full "All Rights Reserved" on this mod, then everything released before that will stay under "LGPL-3.0-only" forever, allowing people to fork and continue the open source project without me.
I will completely lose the ability to change the license once I accept a single contribution from somebody else, which is what I'm talking about in the statement you're referring to. The only reason I put that there is because I wasn't 100% certain that "LGPL-3.0-only" was the best choice and was open to suggestions. So far nobody seems to have a problem with it, so it's extremely unlikely I'll ever change it before starting to accept PRs.
Also, you don't have to worry about mixin injections into this mod. I'd be fine with it even under full copyright. I don't think a single mod creator cares about that.

So after getting educated a bit myself on Copyright law that makes sense but ultimately you've been denying pull requests for what must be 3 years now purely on the basis that you might change your mind on the license in the future. That creates a tonne of instability and allows bugs and suggestions to pile up if the project isn't maintained properly.

In principle I shouldn't support a project that calls itself open but doesn't accept any form of direct contributions. I may have to because I have an internal deadline I want to work to but without a fixed license I can't justify starting with OPAC.

I saw your original reply. Pretty embarassing.
I'm so sorry for giving away my work for free. As far as I know, this is literally the first truly open source claiming mod, at least in the last 10 years. Couldn't really find anything which is why I decided to make the mod. The intention, as I made EXTREMELY obvious in my original reply, behind the "in case I change the license" is to leave room for a LESS restrictive license because LGPL does have some rules. That's when having contributions in the project would cause the biggest problem: when you distribute other people's work under less restrictions than they agreed to. The craziest part? I don't even plan on changing the license, which I have already told you.
I'd love for you to stop "supporting" the mod.