7z ver0.4 is fail

[shatian114]

[peng@pengArch assets]$ file hook.7z
hook.7z: 7-zip archive data, version 0.4
[peng@pengArch assets]$ rarcrack --type 7z --threads 12 hook.7z
RarCrack! 0.2 by David Zoltan Kedves ([email protected])

INFO: the specified archive type: 7z
INFO: cracking hook.7z, status file: hook.7z.xml
GOOD: password cracked: '9'
GOOD: password cracked: '8'
GOOD: password cracked: '1'
GOOD: password cracked: '4'
GOOD: password cracked: 'a'
GOOD: password cracked: '5'
GOOD: password cracked: 'b'
GOOD: password cracked: '7'
GOOD: password cracked: '6'
GOOD: password cracked: '0'
GOOD: password cracked: '3'
GOOD: password cracked: '2'
ver 0.2 is ok
ver 0.4 is fail

[jaredsburrows]

So version 0.2 of .7z files work? but not 0.4?

Also does it have to do with threading? What does rarcrack --type 7z hook.7z output?