With every release of a new iOS, Apple always runs into one issue or the other. This time, with the release of iOS 6.1, issues have started surfacing from some parts of the world, if not all.

From the first day of iOS 6.1's release users of fifth-generation iPod Touch had started complaining about issues related to Wi-Fi connectivity while updating their devices to iOS 6.1.

As time goes by, users of iPhone 5 and 4 have also appeared on tech forums discussing issues they faced while updating to the latest mobile operating system from the Cupertino-based tech giant.

On Apple's discussion forum, a user of iPhone 5 16 GB posted that as he updated his device to iOS 6.1, he lost network connectivity. According to him, the battery drain too appeared once again and his battery went down 40% in just an hour.

"After updating to iOS 6.1, I can't get service anymore. It comes and goes. My battery went down 40% in an hour. GPS can't get a precise location. Phone is practically unusable! I tried resetting network settings, and then restoring the iPhone, but nothing works," the user posted on the forum.

The shocker comes when he goes ahead and shares his whole experience with his phone and the iOS 6.1.

"I went to the Apple Store. They gave me a new phone. More importantly, without 6.1 in it," he posted.

Showing no service is not only this one user's problem, the growing thread on support forum shows that the problem is affecting people across the world.

"I tried iOS 6.1 beta1.2.3.4.5 and now the final release all the versions showing NO SERVICE randomly at places with full coverage  and I can only kick it to work by reset network setting and the network came back for few minutes then NO service again.

Steps I made so far

1- restore to 6.1 betas and final release

2- update from 6.0.2 to 6.1 final release (today)

3- tried different carriers.

4- switched off the LTE / 3G.

None of the above steps worked I'm sure there is bugs causing this issue and it's still in the final release," another user posted.

An iPhone 5 user from Italy posted, "I've got the same problem in Italy on GSM network."

It's not like only iPhone 5 and fifth-generation iPod Touch users are facing problems with iOS 6.1, users of iPhone 4 are also running into trouble while updating their devices to the new iOS.

"Another issue: I updated my iphone 4 to iOS 6.1 last night and now when someone calls it's like my phone is on silent. I checked my settings and everything's the same as it was before the update but NONE of my ringtones work neither the custom or (nor) the ones that were there when i got it," an iPhone 4 user told Mobile&Apps.

Meanwhile, fifth-generation iPod Touch users are still facing issues while updating to iOS 6.1 OTA.

"I have this problem too.  I just attempted to update my itouch to 6.1 (wired) and got an error (3014).  All the help on the apple site is not working. The itouch is now a paper weight," a user posted recently.