The document discusses the history and features of different iPhone models. It describes the original iPhone and its operating system iterations called iPhone OS 1, 2, and 3. It then summarizes the iPhone 4's introduction of an aluminum frame that doubles as an antenna, a higher resolution "Retina Display," the A4 chip, and FaceTime video chat. Finally, it notes that the iPhone 5 was discontinued in 2013 with the release of the iPhone 5S and lower-cost iPhone 5C, which differed from prior strategies of keeping older models at a lower price.

2. Iphone 1
During release, the iPhone was
marketed as running "OS X". The
name of the operating system was
revealed as iPhone OS with the
release of the iPhone SDk. So far,
Apple has released 7 major
software versions for the iPhone,
including the one bundled with
original iPhone units and three
major versions (iPhone OS 1, 2, and
3) for the original iPhone, but
software updates for the original,
3G and 3GS iPhones have been
discontinued.

3. Iphone 2

4. Iphone 3

5. Iphone 4
The iPhone 4 introduced a new hardware
design to the iPhone line, incorporating an
uninsulated stainless steel frame which
doubles as an antenna, with internal
components situated between chemically
strengthened aluminosilicate glass. With
these changes, Apple claimed that the iPhone
4 was the thinnest smartphone in the
world.[8] The iPhone 4 also introduced
Apple's new Retina Display technology; while
maintaining the same physical size and display
resolution as its precursors, its liquid crystal
display had a pixel density of 326 pixels per
inch, which Apple's CEO Steve Jobs claimed
was higher than what a human's retina could
distinguish at an average distance. The
iPhone 4 also introduced Apple's A4 system-
on-chip, along with iOS 4—which notably
introduced multitasking functionality and
Apple's new FaceTime video chat service.
The iPhone 4 was also the first iPhone to be
released in a version for CDMA networks.

6. Iphone 5
The iPhone 5 was officially discontinued by Apple on September
10, 2013 with the announcement of its successor, iPhone 5S, and
iPhone 5C, the latter being a lower-cost variation of the iPhone
5 with similar internal hardware and plastic casing. The
introduction of the 5C deviated from Apple's previous market
strategy, where the previous iPhone model would remain in
production, but sold at a lower price point below the new model.

7. Iphone 15

8. Iphone 9,999,999