I have a machine running 15.04, and while trying to use do-release-upgrade to upgrade it I realised it is forcing me to get 16.04 which I don't want because I know that our code doesn't work well with the updated Python on 16.04.
How can I do this upgrade? (console only)
Update
It seems that even doing an upgrade to current version doesn't work anymore!!
An upgrade from 'vivid' to 'xenial' is not supported with this tool.