is there any action required for somebody running the relay on a pretty bog-standard Ubuntu 12.04 Linux dedi? other than sudo apt-get update && sudo apt-get dist-upgrade
There is a new OfflineMasterKey feature you can read about here:
https://lists.torproject.org/pipermail/tor-relays/2015-November/008190.html
If you want to enable OfflineMasterKey read before upgrading. Otherwise I'd say go for it. Don't forget:
sudo service tor restart
You might see a prompt about a new torrc from the package update. I chose to keep my existing version. There was no noticeable change once the service was back up.