I tried the last snapshot which has changed the ID management and I've noticed that the Old TNT has been removed on this "version". I guess it's an error...
This TNT was on the game with the tag "explode" on true, in 1.12.2 and before... (/setblock ~ ~ ~ minecraft:tnt 1).
We can still have it on 17w45 in the Debug World but in 17w47 this tag has been removed even in the Debug World.
So I would like to know if it's only a bug or if it has been voluntarily removed, because this features is a really nice one for map-making especially.