Per title, Spigot 1.21 has released.

This release will likely break from the usual pattern of dropping all but the latest minor revision; 1.20.6 has only just exited experimental state for Paper. The whole point of multiversion support at this point (for me, at least) is to ease the update process for server owners, so it doesn't make sense to drop a version that people are likely to be upgrading from.

https://github.com/Jikoo/OpenInv/releases/tag/4.4.6

Release will be pushed to CurseForge automatically when completed, and then it's up to their moderation team to review and approve it.

Looks like https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/commits/eae9f760c9849290b9e6ffc08fc93193df206a3d will break opening inventories. Still need to construct our own view from the looks of things, so that'll be a slight retool for 1.21.