My OS is debian squeeze and I installed kde as graphical interface. My current kde version is 4.4.5. But I want to update it to the newest version (4.10.5). How to do it?
According to the packages list 4.10.5 havent made into Squeeze yet. But is avaliable in Sid. You can add Sid packages to your sources.list and install the packages from there. The problem is KDE uses a whole bunch of libs which might break when combined with your current setup. As squeeze is really "old" I'm not sure they will backport kde 4.10 to it. According to here: August 24, 2010 As Squeeze has been frozen, Debian will ship Squeeze with KDE 4.4.5. Unstable repos will have 4.4.5 too until Squeeze release. KDE 4.5.x will be available via other repo some time later.
Seems 4.10 wont make into your release. Hence I suggest you to dist-upgrade.