We hope to support Forge 1.20.1 and NeoForge 1.21.1

[MC-Nirvana]

We hope to support Forge 1.20.1 and NeoForge 1.21.1.

[ff66theone]

That's... a bit more complicated than that.
The project is near-dead, with a single maintainer left, asie, and there has been an attempt to port to 1.16.5 in #3572. There's also OC2, which is more of a successor to OpenComputers than a true port, using a RISC V emulator running Linux instead of a Lua VM (the Linux distro does ship with lua though).
If you have the necessary skills to port all the code from Scala (the language most of the mod uses, and one of the reasons why the mod is mostly dead now) to traditional Java and to make the necessary changes to be able to work on these versions, then go for it.

[Techokami]

Yeah, the version of Scala used by OpenComputers is incredibly outdated and unsupported, version 2.11.1. And upgrading to use newer versions of Scala are not feasible because newer versions constantly break backwards compatability, requiring massive rewrites.

[asiekierka]

with a single maintainer left, asie

I quit even that a few months ago; I think the story of OpenComputers is over.