KGI: Force Touch won't be enough to drive 'iPhone 6s' upgrades, could mean negative iPhone growth

The analyst believes that the so-called "iPhone 6s" lacks a killer app to drive current users to upgrade, as Apple has failed to convince the public that Force Touch is a useful feature with the Apple Watch and recent MacBooks. In comparison, the iPhone 4s added Siri and the iPhone 5s introduced Touch ID —  two features which became industry benchmarks.

As a result, KGI forecasts Apple's holiday iPhone sales to fall between 65 million and 75 million. Apple sold 74.5 million iPhones in the same period last year, its best tally in history.

Kuo made his prediction in a note to investors which was first covered by Taiwanese newspaper Apple Daily.

The latest prediction is a major change of course for Kuo, who said back in April that he believed Force Touch would be the most significant change to date to Apple's iOS user interface. At the time, he suggested that the upgrade would be so large that Apple might consider calling the handset the "iPhone 7," completely bypassing the company's typical "s" cycle.

AppleInsider's own sources indicated back in February that Force Touch would be a key feature of this year's iPhone models.

Aside from Force Touch, the iPhone 6s will likely bring a new "A9" processor alongside a stiffened chassis —  though the overall design should be nearly identical. Other improvements on tap are rumored to include 2 gigabytes of RAM as standard and a faster, more accurate Touch ID sensor.

Apple is expected to announce its new iPhone alongside an updated Apple TV at a special media event on Sept. 9.