how can i update hashcat on bacntrack ?

[philsmd]

You should definitely update to The-Distribution-Which-Does-Not-Handle-OpenCL-Well (Kali) linux first (the version of your operating system is very old!)
To get the newest version of *hashcat, just download it from the hashcat.net web pages:
1. cpu hashcat: https://hashcat.net/hashcat/
2. oclHashcat-lite: https://hashcat.net/oclhashcat-lite/
3. oclHashcat-plus: https://hashcat.net/oclhashcat-plus/