Bukkit

This is a massive update, so below is a non-exhaustive list of changes.

Additions:

• Fully featured API for creating custom Arenas
• Class selection GUI
• Added arena spectators
• Configurable messages
• New event API
• Arena status and leaderboard signs
• Option to balance teams

Improvements:

• Huge performance improvements
• Updated to support 1.7.10 thru 1.10.2
• Various improvements to the existing API
• Updated to use the SwornAPI to avoid duplicating classes
• Standardized class permissions
• Made kill streaks configurable
• Utilize pretty JSON chat
• Greatly improved messages
• Made persistent entities configurable
• Future proofing
• Protect attack dogs from cross-fire

Bug Fixes:

• Fixed whitelisted commands
• Fixed a bunch of miscellaneous errors

Full list of changes: https://github.com/MineSworn/UltimateArena/commits/master
Dev Build Equivalent: http://ci.dmulloy2.net/job/UltimateArena/821/

None :)

If you happen to find one, report it using a ticket.