Apple is ready to start building the rumored 4.7-inch iPhone 6 next week, and will ramp up production of the larger 5.5-inch model during the second week in August. Rumors surrounding the features Apple plans to pack into the next iPhone model have been circulating for months, and more recently have grown to include a late September release which fits with a manufacturing ramp up now.
News of the next iPhone's production schedule comes via insider sources speaking with Taiwan's Economic Daily News (english translation).
Throwing together all the leaks and rumors paints a picture of an iPhone model with a 4.7-inch display instead of the current 4-inch version, an ultra-durable synthetic sapphire glass touch surface, a thinner body that matches the iPad Air and iPad mini, faster processors, improved cameras, and thinner batteries. Rumors also claim a 5.5-inch model is coming, but so far there haven't been any substantial parts leaks to back that up.
A mid to late September launch for the next iPhone fits with Apple's typical release cycle. If that's the plan again this year, Apple needs to ramp up production soon to have an inventory stockpile for pre-orders and launch day.
Apple doesn't comment on rumors, so for now there won't be any confirmation from Cupertino on when the next iPhone will launch or what features it will include. If the production chain is as lax as it was during last years iPhone 5S and iPhone 5C pre-launch build phase, we'll see so many photos from factories the only thing Apple will really need to announce is what day the new models go on sale.