I had to look it up: SLES = SUSE Linux Enterprise Server
There are a number of packagemanagers for suse: rpm, YasT, apt, ...
RPM -> To check which version linux an rpm is built for use: rpm -qpi <rpm-package-name>
YasT -> Info @ novell on YasT
Updates for SLES are downloaded and installed via YaST Online Update (YOU).
When using YasT with rpms, YasT will check the dependencies and install only if the rpm is alright for you system. To be absolutely sure: download your rpm's with YasT.
Some more documentation: