In presenting iPhone users with reasons to upgrade, Apple typically relies on hardware. A new processor, a new camera, HD video, and sometimes, a new form factor. But every now and again, Apple will use software as impetus for upgrading, as was the case with Siri, Apple’s new voice recognition feature in iOS 5 that works exclusively on the iPhone 4S.
Or does it?
Developer Steven Troughton-Smith was able to port Siri to the iPhone 4, as evidenced by the video below. Note though that the iPhone seems to be extremely sluggish. 9to5Mac explains why.
The issue here is not Siri, but is that a special GPU driver for iPhone 4 is needed; and it is obviously not included in the iPhone 4S binary cache – where the Siri files are located.
At this point, Apple’s Siri servers aren’t doing any checks to ensure that Siri requests are coming in exclusively from iPhone 4S devices, and the cynical among us might argue that Siri is more than capable of running on an A4-powered iPhone 4 but that Apple just wants to encourage people to upgrade.
There may be some truth to that, but given that Siri is a new flagship feature, one could also argue that Apple wants Siri to run as seamlessly as possible and that means no A4 processors allowed.
One final theory comes via Mark Crump who tweeted a few days ago that perhaps Siri is iPhone 4S-only because Apple wants to keep the initial requests from Siri “around a million instead of the entire iOS user base” while they tweak Siri and ensure a smooth rollout.