NervesPack 0.4.0 is a minor bump with a fairly big change.
Upgrading existing projects using
NervesPack may require a few changes to get working properly. See the
Upgrading from NervesFirmwareSSH notes for helpful steps on that.
You may also want to update your local
nerves_bootstrap archive to
>= 1.9.0 so that any new Nerves project generated with
mix nerves.new will have this update as well: