Using this repository with slapt-get you'll be able to upgrade your Slackware to 13.1 without complaining about lack of dependency support because I added it for you.
The packages are simply untouched: I have only worked on the PACKAGES.TXT file; go look at http://www.stabellini.net/filesystem/slackware-13.1.
If you want to upgrade using the Slackware DVD, but with dependency support you have to:
- mount the dvd (or iso) in /mnt/cdrom
- download repository.tar.gz and unpack it, for example in /root, obtaining the new directory /root/repository
- add /root/repository to slapt-getrc as a new repository: SOURCE=file:///root/repository
- run slapt-get --update and slapt-get --dist-upgrade.
If you experience any problems or if you have any questions please send me a mail.