The config file was changed, you should either delete your current config or add the changes manually, you can see them here: https://github.com/Olexorus/WitherAC/commit/408cec364ec80cdc98bd73f6268a0eca6dd32d3e

Even if I can't actively work on WAC at the moment I'll of course still update WAC to the latest Minecraft version so you can keep using it when your server switches to 1.16

There was one problem I encountered which I found a fix for that seems to be working really well. Other than that this update was really smooth, even the new soul speed enchantment didn't require any special handling at all. Nevertheless I was only able to do a limited amount of testing so there may be other incompatibilities I missed.

As a bonus I'll also release some other features that I worked on a while ago and didn't have time to release yet.

Changelog 0.21.0:
- updated to 1.16
- added an entity speed check
- drastically improved the high jump / jetpack detection logic, previously it was possible to jump 5 blocks high, now not even 2 blocks are possible
- found a much, much better workaround for Spigot's inconsistent event handling which allowed me to clean up a lot of code and should also fix a few bugs
- performance optimizations and code cleanup