Upgrade to Xubuntu 14.04 (beta) from 13.10

Right now, March 24, 2014, you can try the Trusty Tahr release of Ubuntu. But, for the Xubuntu distro, I did the do-release-upgrade and found no new release. So, here is the trick to upgrade to Xubuntu 14.04:

1. Open the source list file and change saucy to trusty:

$ sudo nano /etc/apt/sources.list

deb http://archive.ubuntu.com/ubuntu/ trusty main restricted
deb-src http://archive.ubuntu.com/ubuntu/ trusty main restricted
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted
deb http://archive.ubuntu.com/ubuntu/ trusty universe
deb-src http://archive.ubuntu.com/ubuntu/ trusty universe
deb http://archive.ubuntu.com/ubuntu/ trusty-updates universe
deb-src http://archive.ubuntu.com/ubuntu/ trusty-updates universe
deb http://archive.ubuntu.com/ubuntu/ trusty multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-updates multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu trusty-security main restricted
deb-src http://security.ubuntu.com/ubuntu trusty-security main restricted
deb http://security.ubuntu.com/ubuntu trusty-security universe
deb-src http://security.ubuntu.com/ubuntu trusty-security universe
deb http://security.ubuntu.com/ubuntu trusty-security multiverse
deb-src http://security.ubuntu.com/ubuntu trusty-security multiverse
deb http://extras.ubuntu.com/ubuntu trusty main
deb-src http://extras.ubuntu.com/ubuntu trusty main

Note: commend out the canonical partner repo:
# deb http://archive.canonical.com/ubuntu/ saucy parner

2. Upgrade to 14.04:

$ sudo apt-get update && sudo apt-get upgrade && sudo apt-get dist-upgrade

3. Enjoy

Note: If you have installed LibreOffice in 13.10 via a ppa, the upgrading will remove it. So, you have to reinstall it again.