With the update, 1.18+ server adjustments must be made to the bukkit.yml file to continue using the correct biome.
The setting should be made regardless of whether the world was / is created with Multiverse-Core!
Example:
Code (Text):
worlds:
The_Name_Of_Your_World:
generator: AlmostFlatLandsReloaded
biome-provider: AlmostFlatLandsReloaded
Bugfixes:
+ Fixed several problems with 1.8 to 1.15.
Added:
+ Support for Spigot 1.19 (and beyond)
Changed:
+ AFLR now uses the new Bukkit API to create worlds, new Minecraft versions will (probably) be automatically supported in the future.