Hi all!

I have just installed SL4.5 at work (I'm really new to linux though actua
lly
using kubuntu 7.04 at home since one month).

Although I already knew 4.5 featured an old kernel as well as old version
s
for different applications (firefox, thunderbird, evolution,...) even KDE
...
Anyway, I had to install this version since I need a compatible GNU/Linux

distro with RHEL 4. 
I need this compatibility to run QuartusII from Altera (an electronic des
ign
suite) that only supports RHEL 3 and 4 (and some suse version).
http://www.altera.com/products/software/products/quartus2/os/qts-os_suppo
rt.html
So, i chose Scientific Linux since it looked more suited for me (working
with microelectronics PhD at university).

At this point, I would like to upgrade/update some applications to run mo
re
updated versions. So, the questions are:

1.- Is this recommended? Will there be any probability the system turn
unstable, ...?

2.- If possible, i think the best way is to add some repos or just downlo
ad
applications binaries/rpms and install them...right? If not, what's the b
est
way?

3.- What about upgrading/updating (still don't know the difference ;-) ) 
the
whole KDE to the latest stable release?

4.- And what I think would probably be the best if possible... Could I ju
st
install SL5.x so that I have a newer system with more up to date
applications while maintaining the guarantee my vendor specific software
will run?

Thanks so much in advance for your help