When saving an item via the in-game menu, NBT Properties will now be pulled. This is VERY helpful as it adds support for plugins like ItemsAdder, ExecutableItems, and other custom item plugins without having to utilize their API (manually adding support).
Would occur when other plugins utilize the ChestSort API with an inventory lacking viewers. Now these calls will simply be ignored since they can't be handled anyways.
If you dropped an item with an interact command while holding it, the command had a chance of being ran. Recent changes broke the old check method for drops resulting in the drops check being ran after the interact event already triggered.
Was causing major lag when the first player joins the server as Spigot was force loading unsafe legacy methods as a result of #setData being called for the move-next itemflag. Furthermore this lag could result in the loss of the item being moved.
1.21.3 contained a change to replace old enums with the registry, this resulted in no longer being able to resolve the old enum names. A change has been implemented to attempt to resolve the old names but it likely will stop working in the future.
Paper changed their ItemFlag functionality in 1.20.5 to be different than Spigot. This change made it impossible to hide default attribute values without setting dummy data.
Please see the documentation page if you need any help with these new updates! If you have any ideas or requests that you would like to see in ItemJoin's future please submit a feature request.