I'm aware you've made it clear that feature requests will only be added to the latest supported Minecraft version, and honestly, 1.12.2 is honestly pretty far from "current", at this point.

Is your feature request related to a problem? Please describe.
In short, I'm looking for a way to not only make custom seeds [while still being compatible with Agricraft], but also add new Mystical Agriculture seed tiers [if possible] in Minecraft 1.12.2.

If you decide to do a backport to 1.12.2, I'd recommend it being a "one time" thing unless it's a VERY serious problem that requires a singular update to fix it.

I will note here that I acknowledge that this is your own decision, and I will have to respect what your decision is either way.

Describe the solution you'd like
The main things I'm requesting is that the backport have the current features of the most recent version [when it was made], and for it to please be compatible with Agricraft [avoiding a "Already Constructing Vertexes" crash], and possibly Immersive Engineering [if you want to].

Describe alternatives you've considered
I have tried Mystical Creations, I'm very aware that mod exists. However, Focamacho has stated here that they don't have the time to make an update to their mod. In the same thread, I did note that I was thankful for the fix they provided for the Vertex Error, which worked for a while since I was just messing around with mod-compatibility. However, as I also mentioned in that thread, I would start working on a modpack sometime this summer [which I am as of this moment].

Additional context
I would like to put out there I'm not trying to be "that impatient guy" or push for anything you don't want to do, I respect your decision either way on this matter.

I would also like to put out there that this doesn't have to be a "one way street" for a solution, if you want to help Mystical Creations make an update, via a fork and pull request situation, it's up to you.

I apologize in advance if I wasted your time with this issue report, wanted to see if you could help.

It wouldn't be possible to backport this mod because the entire thing is based on changes made in the 1.13+ rewrite. I would have to make a new one from scratch, and use a bunch of hacks, which I don't think is worth it.