Most users of iPhone 4s and iPhone 5 might have upgraded their phones to iOS 9, iOS 9.0.1, and iOS 9.0.2 out of excitement when the updates were rolled out. But many are upset as they can't access one of the most interesting features introduced in iOS 8 last year.

We are talking about the WiFi Calling feature that allows iPhone users to make and receive calls, and text message for free as long as a stable and activated WiFi connection is available. The same feature is seen in Apple's latest operating system too, but not on all iOS handsets.

The iPhone 4s doesn't support WiFi Calling even after upgrading to iOS 9 and its upgraded versions. What is more shocking is that iPhone 5 processor clocking at 5 GHz has been stripped off the feature. It could be seen as a move by the company to indirectly force the users of old iPhones to go for new handsets.

Owners of iPhone 5, who have upgraded their devices to iOS 9, iOS 9.0.1, and iOS 9.0.2 will miss WiFi Calling feature as downgrading is not possible since Apple has stopped signing iOS 8.4.1 and iOS 9.

It may be noted that Apple devices that still support WiFi Calling are iPhone 5s, iPhone 5c, iPhone 6, iPhone 6 Plus, iPhone 6s, and iPhone 6s Plus. It is also available in only some countries and only carriers like Bell and Rogers in Cannada, 3 and SmarTone in Hong Kong, EE and Vodafone in the United Kingdom, AT&T, Sprint and T-Mobile in the United States support it.

Well, it's not the end of the world if iPhone 4s and iPhone 5 have been stripped off WiFi Calling feature as there are other alternatives like FaceTime, Skype, Viber, WhatsApp and Facebook.