After much delay, SuperbVote 0.4 is now available. Here's a run-down of the changes:

• BREAKING CHANGE: SuperbVote's handling of invalid matchers has been made more consistent. If your configuration includes a matcher that can't be used (such as an invalid script, or invalid parameters for the chance matchers), SuperbVote will automatically add a matcher that will never match.
• BREAKING CHANGE: Modified the script matcher to take a context object. You can learn more about this matcher on the wiki.
• MySQL is now fully functional. (I have tested using MariaDB 10.2.)
• This release includes a major refactor designed to make the plugin more efficient and easier to maintain.
• Introduced the every-cumulative-votes matcher to allow you to match a reward after every X votes.
• Fixed top voter sign board and top voters scoreboard so that they will work with the latest version of Minecraft.
• Introduced group and groups matcher to allow you to match a reward using groups. This requires Vault to be installed.
• Introduced a migration for SuperbVote's JSON storage format, to allow easier migration to MySQL.
• The migrator now migrates the last time the player voted and displays progress in the console.
• Introduced an update checker for future releases.

Everything in 0.4-BETA is also included. As a refresher:

• Fix bug with world matcher for offline players.
• Switched from custom UUID cache to Bukkit cache. (Fixes 429 and 503 errors, and removes a significant amount of bloat.)
  
• Vote reminder will no longer remind players to vote again if they have already voted that day.
  
• Introduce new chance-percentage matcher to give random rewards with a 1-100% chance, which is significantly more granular than the current chance matcher.
• The current chance matcher is now known as chance-fractional. The chance matcher will become percentage-based in the future.
• Leaderboards have been optimized for MySQL users.
  
• Chances are no longer "deterministic" - they are fully randomized.