Finally 1.13 support has been added! This has been one of, if not the biggest, Minecraft Updates ever released. This update of the Additions API is mostly a compatibility update to be compatible with the new version of Spigot and to mimic the mechanics of the 1.13 release. There's also been a number of bug fixes, and hopefully some improvements to compatibility with PaperSpigot!
Due to the amount of changes made in 1.13, I will now be maintaining two versions of the plugin: One for compatibility with versions between 1.9 and 1.12.2, and one for 1.13 and any future releases. This is done in order to make sure people who haven't updated yet can still keep getting new features and bug fixes. This shouldn't affect anything beyond compatibility.
MAKE SURE TO DOWNLOAD THE VERSION OF THE API THAT MATCHES WITH YOUR MINECRAFT SERVER!