Just upgraded to Ubuntu 13.04, "Rarin' Dang Ringtail".

The upgrade was "smooth as X-Lax" (an over-the-counter brand of laxative).

1) Shutdown Linode
2) Duplicate file image in case of problems
3) Start Linode
4) Login using LISH in case of disconnect
5) As root, run the command do-release-upgrade.
6) It asked if I wanted GRUB installed, I said NO.
7) Reboot

Apache did not start after the first reboot

Reboot again.

All is well according to my tests.

James