So interesting update here, Ragnarok is now official and due to this you will now have to install the DLC so you can play on the Ragnarok server.
We have updated all servers to support this new update. If you play Ragnarok, your builds and items should be safe. We recommend you do not delete the Ragnarok mod folder for the time being due to problems after removing the mod folder after the switch to DLC. It should be safe to remove this folder soon enough though.
To download the latest DLC: http://store.steampowered.com/app/642250/Ragnarok__ARK_Expansion_Map/
Enjoy the latest update!