For those of you, who use Ubuntu 9.04 and would like to have the new features coming with Subversion 1.6, here is a short guide to upgrade from 1.5.
Add the following two lines to your software source list (in /etc/apt/sources.list) …
deb http://ppa.launchpad.net/anders-kaseorg/subversion-1.6/ubuntu jaunty main
deb-src http://ppa.launchpad.net/anders-kaseorg/subversion-1.6/ubuntu jaunty main
… and add the key of Anders Kaseorg to your trusted keys …
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 413576CB
Finally update your package list and do the upgrade:
apt-get update
apt-get upgrade