Thanks, found that it’s still there… https://github.com/deltachat/deltachat-core/issues/210
All deleted messages clearly need to be deleted on the server as well (i.e. synced by default). Accordingly, for a synced client, also all messages need to be downloaded (synced) by default (i.e.if there is enough local storage space). Only this allows to keep multiple client devices in sync.
I think in Cuba you would not need to download any old stuff if a server storage limit is in effect to not keep much messages on the server (only archive them locally).