I was off a few days.
Yes, I understand that Z-Push does not know about the manually entered email address in that case. But when Z-Push obviously cannot determine the correct email address, why does it then send the (faulty) account username in provisioning response, instead of just skipping this?
What's the difference here compared to Z-Push 2.2.x? Before upgrading to 2.3.x this worked fine here with 2.2.x (same iPhone, same account, same IMAP backend etc.). Maybe we could have a config option in IMAP backend to let z-push not send the <Settings:EmailAddresses><Settings:SmtpAddress> provisioning parts and just let the device keep the entered email address?