Update Software Utility
1. Download swaret.
2. Install swaret, installpkg swaret###.tgz
3. Copy /etc/swaret.conf.new /etc/swaret.conf
4. Edit version # from 10.1 to 11.0
5. Type swaret  --update
6. Type swaret --upgrade -a
7. Type swaret --dep
8. Type swaret --purge to clean up
Had some problems with updating with program so I also tried

Slackpkg
Edit /etc/slackpkg/mirrors and enable the mirror of choose, In my case
I enabled gulus.usherbrooke.ca
/usr/sbin/slackpkg update
/usr/sbin/slackpkg upgrade-all
/usr/sbin/slackpkg install packagename