This is a minor update to the plugin which gives it compatibility with 1.21.4. No new features were added as part of this, and its being done primarily to bring back compatibility with newer versions of the API.
Disclamer: This will likely be the last version of the plugin to support Spigot.
Given the time since the last update of this plugin, I decided to perform a functional rewrite of the entire plugin as a way to modernize it. Because of the changes that were made, I believe supporting Spigot will be difficult to maintain going forward. As such I plan to target Paper in the future.
While I am personally not planning to continue supporting Spigot at this time, if there is a push for it and its possible to support it without significant hurdles, I'll be open to accepting PRs to the project which bring back support for it.