Commentators are narrowing down the due date of the latest iPhone refresh, iPhone 5, with evidence mounting to suggest a launch in early September.

In the biggest indication to date, US telecommunications giant AT&T has informed managers to complete any ongoing employee training as soon as possible, in order to be prepared for an influx of foot traffic in September, according to BGR.

The report follows a suggestion on Mac Rumours that Apple is looking to recruit extra staff for the August-September period, even asking former employees to return as part-timers on a casual basis.

Based on previous years, many were expecting the new iPhone to arrive in June or July. It now seems likely the model will be launched in the next two months, to coincide with the release of iOS 5.