WorldBorder is an extremely old plugin and has started to show glitches (teleporting people to the surface when they mining, or teleporting players to spawn).
- WorldBorder is being removed
- There will still be a world border, it will just be the vanilla Minecraft border. The border will remain at 10,000 blocks from 0,0
- The Vanilla border only comes in squares, something I don't think anyone really cares about. Though this does mean that there will be new areas of the map to explore!
There are a lot of benefits to using Minecraft's vanilla world border. For example, players can actually SEE the border, this should help when flying around the End so you don't just fall to your death when you hit an invisible wall.