My wife has been running Ubuntu Hoary on her laptop for over a year now. I intended to upgrade it to dapper and so I upgraded it today - to beat the rush.
It was a jump of two versions, so I decided the the best thing to do was to dist-upgrade to breezy, run all my wife's apps, then dist-upgrade to dapper. I first backed up her home directory to a usb hard drive and started.
The first dist-upgrade was started at about 7:30 in the morning. The laptop locked up solid about a third of the way in, so I ended up doing a bunch of package fixing before I could restart the upgrade. Once that was done, I rebooted, logged in and started all the applications. Everything worked fine.
Next was to upgrade to dapper, so I edited the sources file again, updated apt and then started the next dist-upgrade. This went with no hitches - although I did end up having to manually install some more packages later.
The real problem has been my wife's wireless card. It is a Belkin F5D5010 ver 2. It loads the atmel_cs modules as expected, but then you see a message in syslog that says:
ADDCONF (NETDEV_UP): eth1: link is not ready
It really has me stumped. I did both the dist-upgrades via the wireless card - so I can assume from that this is a new to dapper problem. iwconfig seems to work properly. I did get it to work once. I was messing around manually loading in firmwares and setting the essid with iwconfig. When I re booted and tried to repeat the process, it didn't work - so I'm not sure what I did to make it work - it certainly wasn't what I thought.
I will keep plugging away at this.