Message still stuck forever in outbox

Since years with (the beautiful) K9, if slow or no internet connection, outgoing emails are stored in outbox (Postausgang) with error-message. Till this point it works.
But if internet is back the message(s) stick in outbox, no chance to send it out (the bottom “send it” is without function). The only way to send it, is use the menu “edit as new” (als neu bearbeiteten). This new message is sending , the other is stuck for years.
This bug is in K9 since years. Why I get a lot of updates with new painting and look, but these major bug is blocked since years.
Hope for answer…

Karsten

A related feature that lead me to switch to an earlier version of K-9 is that messages caught in the outbox can be changed to set as unread and moved, on mass, to the draft folder. The latest updated removed these useful features, which is a rare feature of android mail applications. I, personally, would love for those features returned to K-9 and adopted in the replacing Thunderbird android app.

Thank you for your consideration.