This is a public beta release of PlotSquared v6.0.0, the next major release version of PlotSquared. Keeping it short, we already wrote down a changelog going in detail about the changes, additions and issues it addresses, you can find it here.
Read over over it with caution, you may need to adjust a few things beforehand to guarantee a flawless transition, depending on your setup. If not stated elsewise, PlotSquared v6 handles the conversion for you.
As this is still a beta release, taking frequent backups is advised alongside reporting issues to the issue tracker so they can be addressed.
Like Minecraft itself, PlotSquared now requires a minimum Java version of 16 as well. If you didn't update/install Java 16 yet and are unsure how to do that, checkout this guide, it covers the most reputable OSs and host services.