Question on deleting old messages on server

Background:

  • Android version
  • “Delete messages from server” set no Never
  • IMAP Folder Handling: “Watch Inbox folder”, “Watch Sent folder”, “Watch DC folder” and “Send copy to self” all enabled.

If I change “Delete message on server” to any of the existing time, I expect /all/ messages in DC folder to be deleted, regardless of whether they are from contacts who now use DC or contacts who are non-users.

But, would older messages in Inbox or Sent be deleted?

Messages from contacts who now use DC but previously did not? How about those who have never used DC?

It seems that /only/ messages in the DC folder from both users of DC and non-users are delteted. but I wanted to double- and triple-check…

On another note, it would be nice to have additional choices between 4 weeks and one year, maybe 3 months and 6 months could be added? For me, one year is a long time and 4 weeks is a little bit shorter than I would like to keep them.