Hot off the press, just finished publishing this for those interested in running Slackware 15.
Thanks!very useful
I think that one should firs install-new and then upgrade-all:
slackpkg update
slackpkg install-new
slackpkg upgrade-all
slackpkg clean-system (optional! Pay attention what's removed!!)
I would mention slackpkgplus and sbo
[0+9]+_Sbo
[0+9]+alien