Why Siri doesn't like older iPhones

The folks at iFixit believe Siri's lack of support for older iPhones is due to a change in the proximity sensor in the iPhone 4S over previous models. But there are other theories out there.<img src="http://feeds.feedburner.com/~r/cnet/tcoc/~4/V3q7SkVps_s" height="1" width="1"/> [More]