If you use NBTExplorer, you can go into your world, then to level.dat -> data -> datapacks -> disabled, then click on Vanilla, and hit the red 'x' near the top. Hope this helps
Confirmed for 18w50a
If you use NBTExplorer, you can go into your world, then to level.dat -> data -> datapacks -> disabled, then click on Vanilla, and hit the red 'x' near the top. Hope this helps