Thank you very much for the answer.
I did the apt-get upgrade -V and well, it seems that "all is correct" from my inexperienced point of view. But the reason why I do not performed yet the apt-get dist-upgrade is that "kinfocenter" and "plasma-desktop" packages still kept back even with the apt-get dist-upgrade. And as far as I understand "plasma-desktop" is imperative for KDE runs properly. So if I perform the apt-get dist-upgrade I think that after the reboot, KDE will break again.
