Want even more proof that the iPhone 5S, iPhone 5C and iOS 7 will release next month? An internal company calendar has leaked, detailing the holiday times available in September for AppleCare employees at Apple stores.

Apple Insider first published the leaked calendar on Friday, noting time slots appear to drastically decrease between 15 September and 28 September. The report asserted that AppleCare employees cannot request time off during that two-week period.

Read: Apple iPhone 5S: Rumours, release dates and everything you need to know

Apple will allegedly begin selling the next-generation iPhone models on 20 September. That's about 10 days after the company plans to hold a media event. The date also mirrors when AppleCare employees can't go on holiday.

Also, when looking at previous release patterns, Apple tends to roll out a new iOS before selling a new iPhone model. It's therefore likely that iOS 7 will land a few days before the next-generation iPhone models begins selling. Many reports have subsequently pointed to 18 September. Again, this date would mirror when AppleCare employees can't go on holiday.

Read: Apple iPhone 5C: Rumours, release dates and everything you need to know

Apple typically blocks holidays for employees after launch events to ensure the company can meet consumers’ demands in retail stores.

Apple is set to hold an event on 10 September, where it is expected to introduce an iPhone 5S with an integrated fingerprint sensor and a plastic iPhone 5C for budget-conscious consumers. Both phones will purportedly run iOS 7, the next-generation iOS that Apple unveiled at WWDC 2013 in June.

Read: WWDC 2013: Apple announces iOS 7