Question about wip and updating packages

[Ottavio Caruso <ottavio2006-netbsd%yahoo.com@localhost>]

I have looked on the pkgsrc guide and the wip guide but I have only
found answers on how to create a package from scratch, so here it is.

Let's say there is a package in pkgsrc whose version is 0.9. The
package is not strictly obsolete because it might still receive
updates, however it's a bit too old. In the meantime the package
version from mainstream has gone to 2.7.

How could a simple user attempt to make a new package based on the
newer version? Should they reuse the existing makefile and hack it a
little bit and see if that works, or should they make a new package
from scratch, as described on the pkgsrc guide?

And if the build works, should they upload it to wip or notify the
maintainer or eventually also one of the mailing lists?

I hope I've made it clear what I mean.

Thanks