Siri, the much-coveted voice assistant feature on the iPhone 4S, will not be made available to the users of other Apple devices such as iPhone 4 according to Apple's word - a letdown for many iPhone 4 and iPod touch users.

In his blog, Cult Of Mac contributor Michael Steeber revealed Apple's response to one user's bug report.

The user suggested a special Siri build of iOS as a paid upgrade, to which Apple responded, saying,

Engineering has provided the following feedback regarding this issue: Siri only works on iPhone 4S and we currently have no plans to support older devices.

This almost certainly confirms that the only hope for iPhone 4 owners to get Siri is through a jailbroken device, and some hackers claimed to have successfully ported Siri on the iPhone 4, 3G, and iPod Touch 4G.

By tricking Apple's servers into communicating with the Siri program on non-iPhone 4S devices that borrowed the authentication tokens from the 4G, Apple's older devices have proven as capable of running Siri.

To follow the jailbreak world, read:
How To Install Siri on iPhone 4/3GS
Siri Port Fully Functional on iPhone 4 & iPod touch 4G

Previously, it was rumored that Apple was testing Siri on the iPhone 4S and other devices, and even granted its employees special access to a software version so they could use Siri's features without the latest version of the iPhone. This has mounted the expectation for Siri to become available across many Apple devices.

While the dream to port Siri on the older Apple devices may be shattered, the voice assistant is allegedly going to be taken to newer technology, namely, Apple's TV set that is to come. Siri is alleged as the controlling solution for the Apple TV, according to The New York Times. Steve Jobs, Apple's late CEO, had hinted the advanced technology in Apple's TV project before his death.

While Siri, now touted as a beta program, overcomes its frequent outages and immaturity, and progresses to be multifaceted assistant for Apple users, the voice feature remains to be an exclusive benefit for the iPhone 4S users.