In our k0dez, we have a slightly different use for nnrpd -i that is seen in -CURRENT (it omits the 200/201 response and leaves the session open after the first command). ALso, innd's NC_unimp() passes the command to RChandoff(), which takes an extra argument that can be fed to nnrpd -i. It's basically a convenience thing so MODE READER (usually) isn't needed. Want?