Are there any plans to update the mod for 1.21?

Yes. just had a hell of a last 12 months. Multiple stays in the hospital and two natural disasters without electricity for a week each time. I hope to do the 1.21 push for all my mods starting very soon. I'm catching up on easy to fix bugs right now then it's go time.

Okay, Good News, Regrowth for 1.21.1 for forge is uploaded to curseforge and modrinth.
1.21.1 for Fabric is probably a few weeks away.

I'm going to leave this open until I get the Fabric version done too.
Cheers,
Two Guys,
MacTso