It's been just two months since the release of the iPhone 5 smartphone, but already rumors are circulating regarding the launch of its successor device.

Dubbed the iPhone 5S, rather than iPhone 6, some analysts predict that the device will be launched sometime in Q1 2013 while others believe it will be as late as September next year.

The first rumor comes from Taiwanese Web site DigiTimes, which says, "Apple is expected to introduce its next-generation iPad and iPhone series around the middle of 2013, which will boost demand for ICs in particular communications related chips during the latter half of the first quarter, according to the observers. Component orders placed by Apple, which climbed to high levels prior to the iPhone 5 rollout, will rise again between March and April, the observers indicated."

However, the Chinese language website China Times believes the device will be released much sooner, with production expected to begin as early as December of a trial run of between 50,000 and 100,000 units of the alleged iPhone 5S.

Such rumors aren't as premature as they seem. The first iPhone 5 rumors surfaced in Dec. 2011, two months after the release of the iPhone 4S'. However, an early 2013 launch of the next version of Apple's flagship phone is unlikely considering the company's current track record. The last time Apple released a smartphone in the middle of the year was when the company launched the iPhone 4 at Worldwide Developers' Conference 2010, and has since stuck to a fall release date for its devices.

A much more realistic date is provided by Piper Jaffray, analyst Gene Munster, who is reported on Business Insider as predicting a September 2013 release date. Munster believes we'll see the iPhone 5S as a "modest upgrade" from the iPhone 5 next September - around the same time when Apple will unveil its next-generation iPad.

Samsung, Apple's biggest rival in the smarpthone market, is widely expected to release the next version of its Galaxy S4 in May 2013 and is already linked to a range of features including upgrades in its display and processor. However, Samsung has offered no comment on its plans for a Galaxy S3 successor, and like the release date of the iPhone 5S, at the moment, it's all just rumors.