Yettwasezmel 4 ɣef 5 n yetran

sɛur JezUK di Feb. 28, 2019 · aseɣwen yezgan

Nearly perfect - just needs the button to be more obvious that it's activated, perhaps change the text or button background colour.

But why this isn't standard in Thunderbird beats me as it's so obvious Return Receipts are more of an 'as needed' rather than globally always required (where they end up being ignored eventually).

As other's have said, it works on 60.05.01.