Spigot/Paper 1.17
Java 16

probably has a few kinks to work out. Post any new or unresolved bugs on the github issues page.

has new config files

Added console command functionality, using config options for server name and world
Added minimum player count setting. Set to 1 if you want a single active player to generate sleep messages.
Added worlds.cfg, autofilled with world names and default values at plugin enable
Added message lists, selected by world

Rather than just per-world time vs global time, synchronization is now managed on a case-by-case basis in worlds.cfg. This allowed arbitrary grouping and optimization of world selection. I also included environment placeholders for all worlds of an environment.