Have recently been upgraded to Office365, but have an issue with iPhone. I can receive emails OK, and can send via my iPhone - but the sent messages aren't being saved to my iPhone Sent Box. Prior to upgrade everthing worked fine!
Any advice on resolving this would be much appreciated.
Since you are able to send emails fine, it means that your SMTP server settings or network settings are good. I think you need to ask apple regarding the support on this.