I recently did an upgrade from 5.0.6 to 188.8.131.52 and everything went very smoothly. I, however, had a user ask today why they have everyone in their address book, but can not select them from Contacts when she presses the "To:" button.
When she selects to create a new message, everyone from the GAL shows up in the list. When she selects Contacts, the list is empty. I showed her she can enter a *, search, and everyone is there, but am curious why this is needed. She informed me she never had to do this before. Thanks!