The Next Web points at a Guardian online article which states that a next-generation iPhone has been delivered to carriers for field-testing. Without going into much detail as to when exactly Apple might launch iPhone 5 beyond crystal ball peering, author Charles Arthuer writes on the paper’s blog that “my carrier sources tell me that the boxes in which the new iPhone hardware is encased have been transported to carriers for testing”.

The article is referring to the cases Apple (and other manufacturers) use to enclose prototypes so they don’t raise suspicious in field-testing. Remember Gray Powell, an Apple engineer who famously left an iPhone 4 prototype on a bar stool in California? That prototype had been enclosed in an iPhone 3GS-like case and Apple later argued it made discovering the antenna issue that much harder. Of course, Guardian’s article is really a non-discovery as 9to5Mac discovered that the next iPhone hit final testing with Apple in June.

Guardian’s take on those cases? Right below…

The iPhone Air mockup by Federico Ciccarese

The next iPhones go for their testing inside locked and sealed boxes so that the carriers can carry out checks on their network compatibility in their labs. It’s very high security, as you could guess; my understanding is that barely anyone inside the carriers gets to open those boxes, and even when they do the hardware is encased in a dummy body which means there’s no clue to what the actual phone will do. You can bet that Apple has come up with some sneaky scheme that would instantly identify any leak of a phone photo from any of those testing labs; and you wouldn’t want to be the carrier whose employee had done so. (The employee probably wouldn’t stay employed very long either.)

Guardian’s piece does jive with last week’s case leaks from China and a recent iPhone Italia article based on “a very reliable source” from Switzerland carrier Swisscom’s management which also hinted Apple had already contacted carriers around the world to make necessary arrangements for the iPhone launch. That source called for a September launch in the United States followed by an October release to international markets.