Did an update from 7.0 to 7.1. During the update I probably lost the mirror. Started the process again. Went smooth. Had to set up a virtual domain again - emails have not been delivered to the users belonging to this domain. Seems now, that everything is working fine.
I checked the packages with yum.log. Doing ie. a
rpm -q libgcc results in
libgcc-3.4.5-2
libgcc-3.4.6-3
There are now some packages with different versions - are the packages with the lower versions to be removed? (rpm -e)