Apple has come under pressure from a Chinese consumer group demanding answers over the slowing iPhone debacle.
The Shanghai Consumer Council wants an explanation from Apple about the slowing of older iPhones following software updates.
In a letter to Apple this week, the council requests an explanation for the slow-down and information about what Apple plans to do to remedy the issue.
The non-government organisation claims to have received 2,615 complaints about Apple products and services in 2017 versus 964 complaints in 2015.
Earlier this month, Apple was also asked by the US Senate committee to answer questions about the iPhone problem.
Apple issued an apology on December 28, cut battery replacement costs and pledged to change its software to show users whether their phone battery is good.