To upgrade to the latest version of emoncms:
1) Download the latest version and unzip to your chosen server directory
https://github.com/openenergymonitor/emoncms3
Or if you use git, use git clone when installing for the first time:
git clone git@github.com:openenergymonitor/emoncms3.git
and then all you need to call is git pull and it will download and update the latest changes.