A couple of months ago I was asked to push code change for Samogotian. (At the time I hadn't have regulated my membership on this mailing list, then I forgot it.)
But Samogotian is not the only code to be fixed. Basically, we should make the decision and suggest to the Board/staff/Phabricator to proceed with that. I see that None of the cases I am suggesting is in any way problematic, as well as those names are already implemented into the interwiki codes.
bat-smg => sgs be-x-old => be-tarask fiu-vro => vro roa-rup => rup zh-classical => lzh zh-min-nan => nan zh-yue => yue
I don't know if you already did or not this, but I think it's time to push it.
In relation to the old codes, I think they should stay as "permanent redirects" as long as there is a traffic to them. They won't be used in any other case, so we don't need to hurry in relation to their removal.