I already installed Karmic Koala on my test partition but not on my main machine, until now. I finally mustered my courage to upgrade my Jaunty Jackalope to Karmic Koala and to  make sure I have enough time troubleshooting I did it in this weekend, which is a long weekend.
I took the safest path possible (safest doesn't mean 100% safe and trouble-free, mind you) and that is  to upgrade from CD, from ubuntu-9.10-alternate-i386.iso to be precise. By upgrading from a CD, there's no risk of  network problem in the middle of upgrading process. Read the detail on how to upgrade using alternate CD here.
The upgrade process took about 1 hour, which was went very smoothly.

Like I said it's not a trouble free process, here are problems encountered after upgrading to Karmic Koala :

• the most common problem is that Karmic is unable to load Linux Drive, so I anticipate it by editing the grub first after the upgrading process finished and before restarting. By upgrading from 9.04 it means I won't have the new Grub2 and still use Grub legacy, no problem I like old Grub more.
• shift key is not working,
  solution : open Start Menu -> System Tools -> Configuration Editor, and then go to apps -> metacity - > global_keybindings -> run_command_1. Change the value from Shift+F19 to disabled.
  

So far so good :)


keyword : upgrade, 9.04, 9.10, jaunty jackalope, karmic koala, shift key not working