For the past five years, Apple's September iPhone-centric events have followed the same general formula. An event during the first week or two of the month, pre-orders shortly after, and then an official launch date approximately 10 days later. Apple's September schedule for 2012 to 2016 is below:

- iPhone 5 (2012) - Sept. 12 event, Sept.14 pre-orders, Sept. 21 launch.

- iPhone 5s (2013) - Sept. 10 event, no pre-orders, Sept. 10 launch.

- iPhone 6/6 Plus (2014) - Sept. 9 event, Sept. 12 pre-orders, Sept. 19 launch.

- iPhone 6s/6s Plus (2015) - Sept. 9 event, Sept. 12 pre-orders, Sept. 25 launch.

- iPhone 7/7 Plus (2016) - Sept. 7 event, Sept. 9 pre-orders, Sept. 16 launch.

If Apple plans to follow this same formula -- and it looks like that's what's happening -- pre-orders for the new "iPhone 8" and its companion devices the iPhone 7s and the iPhone 7s Plus will take place on Friday, September 15 at 12:00 a.m. Pacific Time.

Following pre-orders, the new devices will most likely see an official launch on Friday, September 22, with pre-order shipments going out to customers and in-store stock available.

Friday, September 15 is a highly logical guess as to when we're going to see pre-orders, and unsurprisingly, that's the date being cited today by German site Macerkopf . According to the site, German carriers are preparing for a September 15 pre-order date and a September 22 launch date.

While Apple tends to follow a specific September formula, there have been deviations. In 2013, for example, Apple did not accept pre-orders for the iPhone 5s due to supply constraints, and in 2015, pre-orders took place early on a Saturday morning. Still, September 15 and September 22 are the most likely dates for pre-orders and launch, respectively.

Apple will unveil the new iPhone 8 at an event set to be held on Tuesday, September 12 at 10:00 a.m. PT at its Apple Park campus. An iPhone 7s, 7s Plus, LTE Apple Watch, and 4K Apple TV will also make an appearance at the event.

For details on the new iPhone 8, which will feature a glass body, edge-to-edge display, facial recognition, and more, make sure to check out our full iPhone 8 roundup.