Opinion Apple CEO Steve Jobs duly stood up at the company's World Wide Developers Conference in San Francisco this week to introduce the long-awaited iPhone 4.

This has become almost as much of a June tradition as Wimbledon tennis, but there was a clear difference this time around. To a far greater extent than on the previous three occasions, Apple faces some real challenges in the smartphone world, and it was not clear that the neat hardware and multimedia enhancements in iPhone 4 would be enough to meet them.

As Microsoft well knows, a product is most vulnerable when it becomes a sacred cow, so dominant that nobody dares rethink it. Although Jobs boasted of the "biggest leap" since the original iPhone, and of about 100 new features, the new gadget delivered nothing really game changing. No CDMA version or LTE roadmap, no real tinkering with the famous user experience. With HTC's top end phones breaking records in several markets and Android making steady progress, Apple may need to do more to hold onto its crown.

To be fair, for most handset makers the changes Apple did make would have been eye catching, and it may have been right to focus the enhancements on hardware design, where the iPhone often lags behind rivals as it does not in user experience. In particular, the unimpressive camera system has been overhauled and the new model is ultraslim, at just 9.3mm thick.

The most impressive new feature is a very high resolution display, at 326 pixels per inch. Apple has set itself up against the main trend in advanced smartphones, AMOLED screens. It claims its new Retina Display is "superior" to OLED, with Jobs employing his usual hyperbole. "There has never been a display like this on a phone," he said. iPhone 4 will pack four times more pixels into its 3.5-inch touchscreen than the 3GS, with a 800:1 contrast ratio.

Jobs said there were over 100 new features, many of them already well known to the blogs, and he focused on eight of the most significant. The first was the slimness - the latest iPhone is 24 per cent thinner than its predecessor, and Jobs claimed it would be the "thinnest smartphone on the planet".

Some of the enhancements were catch-ups, notably on the camera front, where the iPhone family always under-delivers. Now, at least, the handset has a front-facing camera - present on most smartphones for video calls - and LED flash. In fact, it has a whole new camera system, though this still only achieves the five megapixels that is average for smartphones - better than the 3GS model's three, but nowhere close to the 12 achieved by Sony Ericsson, Samsung and soon Nokia, or the eight of Motorola's latest Android device, Droid Shadow/Milestone XT720.

More innovative was a stainless steel band around the new handset, which forms part of the antenna system. "Stainless steel for strength. Glass on the front and back. Integrated antennas, and extraordinary build quality," was Jobs' boast.