After giving out a free replacement for faulty iPhone 6s batteries, Apple has directly addressed the issue behind the problematic units.
In a statement, Apple said that "a small number of iPhone 6s devices made in Sept. and Oct. 2015 contained a battery component that was exposed to controlled ambient air longer than it should have been before being assembled into battery packs. As a result, these batteries degrade faster than a normal battery and cause unexpected shutdowns to occur."
The company also insisted that the problem was not a safety issue.
"We looked for any other factors that could cause an iPhone to shut down unexpectedly. After intensive investigations, no new factors have been identified," Apple wrote.
Earlier, some customers from China complained that their iPhone 6s units shut down randomly despite having at least 30 percent of the battery's capacity. In response to this, Apple said that it will be providing free replacements for units manufactured within the given time frame.
Apple also stressed that the iPhone turns off automatically when placed in certain conditions.
"We also want our customers to know that an iPhone is actually designed to shut down automatically under certain conditions, such as extremely cold temperature. To an iPhone user, some of those shutdowns might seem unexpected, but they are designed to protect the device's electronics from low voltage," Apple said.
According to China.org, Apple's statement came a day after a consumer rights protection commission disclosed the total number of complaints against Apple in public.
"The commission [had] received 1,221 complaints about Apple in the two months to November 30, which was nearly six times higher than the same period of last year," reported China.org.
Among the major problems were unexpected power-offs, stolen accounts and combusting batteries, said the commission in a statement.