Issue #14426 has been updated by Pieter van de Bruggen.
As mentioned in #14428:
`install`, `list`, `uninstall`, and `upgrade` all respect the `--modulepath`
option for specifying module locations (and this *should* be documented), and
this is the preferred way to specify a standalone
Issue #14426 has been updated by Anand Kumria.
Confirmed that:
puppet module upgrade --modulepath=mtest akumria-nullmailer
works as expected.
So this is more of a documentation / usage problem.
Bug #14426: upgrading a module is not possible
