FOSS gamedev and creative worlds

I need a command to get rid of unkn-owen-blocks ive got other mods that dont work on latest version and wnt my old map so now there is unknowen blocks every where? can this be fixed easy? there are lots of them by the way...

Well I think a command like /clearunknownblocks would be useful. Have it's only use being to clear any unknown blocks on the map. Barring that, I think admin tools has a stick that can remove unknown blocks (but haven't tested it).