I guess this smell newbie a long way - but here I go

I have just installed Salix Fluxbox. I first had the problem that I had selected a repository mirror that was down - so I have changed it to http://slackware.org.uk/salix
I have noticed that in gslapt package manager, many of the avaiable programs have a version number that is several years old.
Is there different packages, if changing repository source?
Really noob question from me:
Let say I want to get the newest version of Inkscape. How can I get that in Salix Fluxbox, if possible? (have never compiled anything so ino order to do that I have to read some guidelines etc).
Thanks