The much-rumored iPhone 5S is reportedly ready to go on pre-order on June 20, ahead of a launch in July.

According to a leaked document reportedly meant for employees of Japanese telecom KDDI's "au" wireless service, the carrier will start taking pre-orders for the iPhone 5S on June 20.

The alleged document was obtained by French website Nowhereelse.fr and appears to be meant for sales floor staff and carrier pricing information. It does, however, mention some details regarding the yet-to-be-announced iPhone 5S.

The document may or may not be authentic but, as AppleInsider notes, the laminated paper does seem very similar to the current product and pricing "cheat sheets" many cellphone dealers and official carrier stores in Japan refer to. On the other hand, such cards are easy to reproduce — some of them are printed directly at point-of-sale from a PDF file, and the company logo is the only distinguishing feature.

The information for the iPhone 5S "new product" appears written and starred in red, and the handset seems set for a pre-sale announcement on June 20, with actual sales starting in July. Below the release dates, the document lists a notation for major future changes the next-generation iPhone will bring. In this case, the alleged changes include a fingerprint reader, a 13-megapixel camera and iOS 7.

The areas highlighted in green, meanwhile, offer information regarding the carrier's current monthly plans for the iPhone 5. Those plans include LTE flat-rate plans, as well as family calling subscription offerings and a cash bundle offer for the telecom's "hikari" home Internet service users.

The information in this purportedly leaked document is in the rumor state for now, so take things with a grain of salt. It does, however, fall in line with the timeline for Apple's upcoming Worldwide Developers Conference (WWDC), which will take place from June 10 to 14. If the Cupertino giant were to unveil the iPhone 5S at WWDC, it would be one week ahead of the June 20 pre-order date listed in the KDDI document.

While lots of speculation currently surrounds the upcoming WWDC conference and Apple's plans, Apple stays mum as usual, so nothing is for certain. Could the purported iPhone 5S arrive as soon as July?