I'm working on a world that I started way back in 1.11.2, and have been updating it through each major update up till now in 1.13.2, where they changed all of the light calculations of water.
The world's water light levels haven't been updated automatically, but manually placing blocks and breaking them in the dark spots will cause it to update. All the water areas I've done work on have been updated to the new light levels manually. The problem is, the size of the playable map area that I care about is about 280 MB, with all of the water needing to be updated being the ocean surrounding the main landmass. Anything beyond that should be brand new superflat ocean chunks with a water level of 20.
at the normal regular ocean depth, the light level difference evens out, so those could probably stay as they are, not really in an area I care about anyways, but my coast lines should be updated to avoid an inconsistency with other areas with the new light levels.
I have been running this map in paper with the bukkit world edit plugin for 1.13.2 to try to replace the loss of MCEdit.
Anyone experienced with World Edit know of any tricks to force light recalculations of an area? Setting an area with world edit doesn't seem to do the trick.
I have started a little with a few command blocks that place a few spaced out blocks and then deletes them. It kind of works, but it is kind of hard to operate, and still takes awhile.