Apple's latest flagship smartphone, the iPhone 5S, hit store shelves a little more than a month ago and has been a popular commodity ever since. However, Apple is not a company that is content with resting on its laurels for too long. As a result, sources close to the company report that it is well on its way toward testing new product ideas for the next installment in the iPhone family.

Two models planned for release in the second half of next year would feature large displays with glass that curves downward from the edges of the phone according to an unnamed source cited by Bloomberg News.

It's been rumored for a while that Apple is planning to throw its hat into the ever expanding market of smartphones with large display screens. According to the report, there are 4.7-inch and 5.5-inch models in development, each would be the biggest iPhone to date and will compete directly with the Galaxy Note 3 from Samsung.

All of these models are still development models. The company is merely working out plans that have not yet been completed. The company likely will release the prototype in the third quarter of next year.

Bloomberg's source also points to a prototype with pressure-sensitive sensor that can distinguish between heavy and light touches on the screen. However, testing for this feature likely won't be done in time for it to be featured on the iPhone 6 and is likely slated for a later version of the flagship smartphone.

The iPhone 6 is largely the topic of rumor but many people are expecting it to feature a larger display to compete with the emerging market for phablet-sized screens. As for the news of a curved or flexible display, many new smartphones are starting to offer a curved design but the product has not exactly caught on yet. It remains to be seen if any of the elements being incorporated into the iPhone 6 prototype will find their way to retail stores next year.