Manual juju upgrade

[Henning Eggers]

Hi,

I have a couple of machines running an older juju version (1.16.6 on precise)
and I cannot manage them through my current workstation installation (1.20.1
on trusty). I get errors like "no such request "FullStatus" on Client" and now
even a panic and stackdump (that's new).

The environment only has 4 units. Since I cannot run (or rather don't dare to
run) upgrade-juju right now, can I upgrade them manually through ssh somehow?
Does the control bucket or environment file need upgrading, too?

Any help appreciated. ;-)

Cheers,
Henning