How can I inform an XMPP sender of other clients sending messages on the sender's behalf?

Get your server vendor to implement XEP-0280 : Message Carbons. Then you'll need to turn it on in your client.

Get your server vendor to implement XEP-0280: Message Carbons. Then you'll need to turn it on in your client.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.