The newest update requires the Library of Utils mod. It's another addon that ensures the mods' reliability without the author needing to deconstruct the whole code to figure out what's wrong in case of a crash.

Q: Does this work in single-player?
Yes. As long as you have the Library of Utils installed.

Q: Does this work in local servers and multiplayer?
You're the host: Yes, as long as you download and install both mods for it to work. If you download Dynamic Lights without the Utils mod, then it will not work and all players won't be able to see this.

Again, as long as the host installs both mods - All players can view it without having to install it on their end.

You're a player in someone else's lobby: Depends on whether the host installed it or not. If the host didn't install it, you won't see it on your end either.

You're playing in single mode with bots: If you download and install both mods, then yes. You can see it.

Q: Does this mod still work in 20XX or any year that I find this thread from now?
Yes. Did you install both mods?

Posting this now for those who might find this in the future, including myself should I accidentally uninstall the mod.