For months, there's been speculation as to when the iPhone 5 will be released, and what high-tech wizardry it might boast. Early rumors included talk of a bigger screen, an aluminum case, and near-field communication (NFC) technology. In recent weeks, a number of additional rumors have emerged. Here are five:

1. A curved glass display
Digitimes, an electronics industry newspaper for Taiwan and China, reports that Apple bought hundreds of glass-cutting machines to make a concave display screen. A number of newer phones, like Samsung's Nexus S and LG's G2x With Google, have curved displays, which can make holding a phone to your face more comfortable.

2. Availability on more carriers
Apple analyst Peter Misek, of Jefferies & Co. says he expects the next iPhone to be available on a number of new mobile carriers, including Sprint, T-Mobile, and China Telecom. He notes that on the last Apple earnings call, management responded to a question about carriers by saying, "We are constantly looking and adding where it makes sense, and you can keep confidence that we'll continue to do that."

3. Better global coverage
Because the current Verizon iPhone uses a CDMA chip instead of the GSM chip used by the rest of the world, its international coverage is very limited. But, with the next iPhone, Verizon will have global coverage equal to AT&T's, according to Verizon CFO Fran Shammo.

4. A delayed release
While Apple has not announced a release date for the iPhone 5  (many are expecting September), its release could be delayed after a tragic explosion last week at Apple's Foxconn factory in China killed three people, and injured 15. Foxconn released a statement saying that iPad 2 production would not be affected, but it's unclear if the next iPhone might be.

5. No big changes
The next iPhone may not even be the iPhone 5, says Misek. "According to our inductry checks," it will be the iPhone 4s, and have only "minor cosmetics changes, better cameras," and a faster processor.

Sources: Digitimes, PCMag, All Things D, Reuters, Computerworld, Forbes