Sorry for creating a new post on this topic: the forum advised me to do so since other posts are quite old.
I wanted to ask if you planned to allow setting minimum stock for Local Mail, or if the lack of this feature is intended and won't be changed.
As many players, I think it would be an extremely convenient quality of life change, especially considering that excess Mail at the destionation port is always dropped and lost, and it would make airmail planning much much much easier
I am aware that mail is being stored differently than other goods, hence implementing "minimum stock" option isn't perhaps immediate, but it could be done (for example) in the Airship Trading Post - Mail Module UI, by clicking on the relative Local Mail icon. Arctic and New World Science Reports could allow that too, since both goods can be withdrawed from the island (unlike Regional and Overseas Mail).
Hoping that this feature will be included or at least that it will be stated on the WNF/NAD tab of the "Known Issues List" Trello Board