Spigot has decided to discontinue distribution of the Bukkit artifacts, which means Bukkit "doesn't exist" after Minecraft 1.15. This commit takes the plunge on that change and moves to the Spigot API rather than the Bukkit API. Goodbye, Bukkit. Hello, Spigot. The version is also bumped to 1.17 to give way to new features and bug fixes otherwise blocked by staying on 1.13. Unfortunately, this brings with it a swath of potential issues with version compatibility going forward, because backwards compatibility in the API sometimes takes a back seat, such as with the Material and EntityType enums. This commit specifically changes some references that break compatibility with older server versions, but compatibility with those is reinstated later. Finally, the Spigot repository is changed to match the consensus about which path on the Spigot Nexus instance to use. This seems to be what everyone else is doing, so `bandwagon.jumpOn()`.
MobArena 
MobArena is an arena-style minigame for Spigot-based Minecraft servers
Getting Started
If you don't want to compile the plugin yourself, grab a release artifact from one of these two sites:
The wiki here on Github should have all the information you need to get started using the plugin.
Getting Help
If you run into problems or need help with something, feel free to hop on the MobArena Discord server to have a chat: Instant Invite
Remember, though, that this communication channel is idle chat, which means you likely won't get a response immediately. It could take anything from a couple of seconds to a day, but your message will be seen.
Contributing
Found a bug, got a suggestion, or want to dig into the code base? There are many ways to contribute to the project!
Get started here: Contributing