How can I get v6 for ubuntu trusty?
I'd suggest using the Linux standalone build if your distribution
has not yet packaged a new enough version of git-annex.
Or file a bug on your distribution of course, to get them to be more
proactive. git-annex v6 is at this point 9 months old, and has been
in Debian since at least May, so I don't know why Ubuntu would be lagging