Note the date: 21 September 2012 is when the iPhone 5 will launch after a 12 September reveal, according to more sources with knowledge of the matter.
If the 21 September date sounds familiar, it's because the date was already being bandied around earlier in the month by French blog site App4phone.fr after it learnt that a large Chinese accessory-maker had been told directly by Apple to be prepared for this date.
This time it's Apple news site iMore which supposedly has the details of the launch of the next iPhone.
"iMore has heard that Apple is planning to debut the new iPhone at a special event on Wednesday, September 12, 2012, with the release date to follow nine days later on Friday, September 21. This information comes from sources who have proven accurate in the past," reports the site.
According to iMore, the iPad mini will also be announced at the same September 12 event, as will the new iPod nano, but the site hasn't managed to find out a release date yet.
The timings do make sense: it's the same time frame as the launch of the iPhone 4S as well as meaning Apple would avoid clashes with the Microsoft juggernaut planned for October.
Microsoft is planning on dominating October this year with several high-profile launches including the launch of the Window 8 operating system, the Microsoft Surface tablet, the launch of SmartGlass on the Xbox 360 and Halo 4, as well as the expected launch of Windows Phone 8.
If Apple were to launch the iPhone 5 in September, this would allow the company to avoid any clashes, but also make sure the new iPhone and iPad mini featured in any comparison with anything Microsoft was launching.
It also means that Apple wouldn't have to compare iPhone 5 sales directly with iPhone 4S sales as they fall into different financial quarters, something Apple likes to do so it can boast huge increases in sales for the same quarter of the previous year.
Of course iMore could be guessing, however with two independent sources now claiming the same time frames, connecting the dots and making sure 2 plus 2 equals more than four and end of September release date is looking more and more likely by the day.
UPDATE 30 July: Now All Things Digital, the tech section of the Wall Street Journal, is also claiming its sources confirm the 12 September event date:
"Sources tell AllThingsD that Apple is currently planning an event for that week. And while we haven’t yet confirmed its focus, history suggests it will indeed be the new iPhone."
UPDATE 31 July: Following the "confirmed" stories above, Reuters, Bloomberg, and the New York Times are all now also claiming they have independent sources close to the matter that are confirming the 12 September launch date.