Ubuntu 10.04 LTS is EOL April 2015
Ubuntu 10.04 turns 5 this month. This means that it will officially be end-of-life. We need to decide what this means for our gitian guest VMs for Linux. I think if we transition the Linux builders to 12.04, we risk incompatibility with Debian/oldstable, Debian/stable and Centos 5.x, due primarily to a slightly newer glibc in 12.04 than those systems (12.04 uses glibc 2.15, where as Debian/stable went with glibc 2.13-and-change).
I think my preferred option long-term is to switch us to Debian guest VM images, but it looks like the only way to do that is to also switch to using a sketch python-vm-builder fork completed as a Summer of Code project way back in 2009: https://wiki.debian.org/VMBuilder
The Bitcoin people must be dealing with this issue as well. We should see if we can find out what they are doing.
This is probably also something we should postpone until after 4.5 is out, due to the potential build incompatibility and build system stability issues.