Hello and thank you for your interest in this plugin!
I would like to support Spigot 1.13, but I am unfortunately having some issues that are preventing me from doing so. More information on this is available here:
https://www.theprogrammersworld.net/forums/viewtopic.php?f=16&t=25#p63
If you are willing and/or able to assist me with resolving this issues, I would be grateful.