Minecraft World of Color was released on June 7th, 2017. I neglected to update the server for quite some time, but after some testing and updates, it's back up and running with this latest patch from Mojang. For those of you following along at home, the only thing required on your end is to run your launcher and it should install and unpack the v1.12 client when you click "play." Be aware that if you're using the profile editor to specify a Minecraft version, you'll need to switch to a profile that's following the current release cycle before it'll update.
This version brings a bunch of interesting changes, including colored concrete, to Minecraft and revamps the achievements system, replacing it with advancements. There appears to be a recipe book as well, but I believe it only tracks currently known or discovered recipes (helpful for new players).
Enjoy!