From level Armani_Natural-born_R2V4.nxlv (Contest 27 entry, can't usefully link because I backrouted it and Icho will delete older versions of contest levels):
TITLE Natural-born
AUTHOR Armani
MUSIC dropthebeat
ID x55D5AD0151E8EF4E
VERSION x000000000000001C
From replay of that Natural-born v4:
USER Simon
TITLE Natural-born
AUTHOR Armani
GAME Contest_27
GROUP Contest_27
LEVEL 10
ID x55D5AD0151E8EF4E
VERSION 28
Compare the final quoted line of the level with the final quoted line of the replay: One is decimal, one is hex. To see that 0x1C = 28 isn't trivial, thus it's unnecessarily hard to see if the replay has really been played against that level version.
The ID is hex in both cases, that's fine. The version should also be identical in both cases, either both hex or both decimal, probably both decimal.
-- Simon