Apple acknowledged this week that an iPhone 6S shut-down problem is now a serious problem for the company. The Cupertino-based company has announced that the next iOS update will include diagnostic tools, which Apple will use to collect more information why some iPhone 6S phones are shutting down unexpectedly.

After having received reports on the iPhone 6S shutting down, Apple admitted that its iPhone 6S has a battery problem. The company said the iPhone 6S issue is real after China's Consumer Association issued a warning together with the pressure from thousands of Chinese iPhone 6S users.

Apple admitted this in its official website for the People's Republic of China. However, the company did not repeat the disclosure on its official U.S. website.

Apple has already confirmed the iPhone 6S issue last month, but the problem was limited only to the iPhone 6S devices made from September to October 2015.

But today's latest problem runs deeper. Apple's latest problems show that it doesn't know why some of its iPhone 6S handsets are turning off unexpectedly although the phone's battery indicator showed more power remaining.

Fortunately, the Cupertino-based company has some good explanation why the iPhone 6S is unexpectedly shutting down. Apple blamed the "ambient air" that causes the iPhone 6S's battery shutdown. A small number of devices manufactured from September to October 2015 contained a battery component that was exposed to controlled ambient air longer, which shouldn't be, according to some IT experts.

To deal with this, Apple has set a massive battery replacement program for the iPhone 6S. It also announced plans for a diagnostic tool to collect more date from users to find solutions in the upcoming update. iPhone 6S users can get a battery replacement for free while iPhone 6 Plus users have to pay $149 to get a replacement and solve the problem.

With the iOS update, Apple will be adding a diagnostic feature that will collect data. These will contribute to the algorithms for better battery performance and management, according to Apple Insider.

Besides the iPhone 6S shutdown issue, other customers also experienced major problems on their iPhone 6. The latest and one of the biggest issue is the "30 percent bug." The problem covered other iPhones that were released over the last 4 years, including iPhone SE, iPhone 6S Plus, iPhone 5S and iPhone 5.

According to Forbes, Apple has found a small amount of iPhone 6S users who were dealing with the "30 percent bug" that causes the phone to shut down when it reaches the 30 percent battery remaining mark. Apple said these were part of a feature they installed recently. The problem is that the installed feature can cause the iPhone to shut down when they are exposed to extremely cold conditions.

Finally, some of the features expected for the update include the latest emoji from Unicode, a TV app and single sign-on support for all TV providers, and some additional features for iMessage, according to phonearena.