In another sign that the iPhone 5 will be released in October, Verizon is offering the iPhone 4 to select customers for $120 through Friday, even as Apple maintains its code of silence.

Verizon is conveying the $120 iPhone 4 offer to existing customers by a text message. The offer is customer-specific, meaning that only if the customer has received a text message will he be eligible for the early upgrade. The deal requires a new two-year contract.

The iPhone 4, which was released on June 24, 2010, is already more than a year old, a long period for the mobile industry considering the rapidness with which the technology is developing. So consumers will think twice before buying the iPhone 4 even at such a low price.

It is expected that the iPhone 5 will be running on iOS 5. This is a critical aspect to be considered before accepting the offer from Verizon, since the older iPhone normally will not be capable of running all of the features found in the latest version of iOS.

Verizon's sale on the iPhone 4 has also intensified speculation that a midrange smartphone will be launched along with the release of the iPhone 5.