Following this week’s announcement that the iPhone 4S will be including the Siri Assistant feature, Apple appears to have removed the standalone Siri app from the App Store. Existing Siri app users are also now seeing a note in the Siri app indicating that an “even smarter and better-looking” version is on the iPhone 4S, and suggesting that standalone app will stop working on October 15th—the day after the release of the iPhone 4S. The new built-in Siri Assistant demonstrated by Apple this week will be exclusive to iPhone 4S users, however as the prior app works fine even on the older iPhone 3GS, it remains unclear what changes have been made to the new implementation of Siri that require the new iPhone 4S hardware.