Apple is facing a class-action lawsuit again over excessive data usage on older iPhone iterations powered with iOS 6, 7 or 8. This is the second time in a year, after the company was hit with a similar legal claim in October.

Filed in the US District Court for the Northern District of California on 17 December by Hagens Berman Sobol Shapiro LLP, a law firm that works for protecting the rights of consumers, the lawsuit claims users of iPhone 5s and iPhone 5 running on older versions of iOS – such as iOS 6, 7, or 8 – faced an issue, wherein their devices automatically switched from Wi-Fi to cellular data while streaming videos or engaged in other activities, resulting in consumption of large amounts of data.

The issue was fixed for Verizon subscribers in 2012 through an update released for iPhone 5 users. An investigation by Hagens Berman suggested Apple had not fixed the problem for AT&T subscribers and it remained an issue for other users as well. This seemed to have affected all versions of iOS 6, 7 and 8, but was only resolved with the iOS 8.1 released in October 2014.

The firm further says: "We believe Apple should not have withheld this repair for AT&T Wireless subscribers for any period of time. By withholding this information and repair, consumers were unaware of the defect and were left to sort out high cellular data charges with their wireless carriers."

In October, Apple was hit with a lawsuit due to the Wi-Fi Assist feature in iOS 9. It was alleged that the company had failed to explain to users that it used data from their cellular plan. The plaintiffs – William Scott Phillips and Suzanne Schmidt Phillips – claimed they incurred overage charges on their iPhone 5s units after upgrading to iOS 9. They claim the "overall amount in controversy exceeds $5m".