Apple has agreed to settle a long-standing class-action court case in the US over claims it deliberately slowed down older iPhones as far back as 2015.

Apple was accused of making its handsets – ranging from the iPhone 6 up to the iPhone 7 Plus – run slowly, causing apps to lag and services to stall, in an attempt to encourage affected users into upgrading earlier than may have done normally.

In December 2017, a class-action lawsuit was brought against the tech giant by a group of disgruntled iPhone owners who demanded some form of compensation for having to pay out for new phones unnecessarily.

Apple admitted to slowing down the phones but not as a ruse to get them to upgrade. Instead, the company said the slowdown was necessary to increase the lifespan of the phones by protecting their batteries.

In response, Apple launched a cut-price battery replacement initiative, which fixed the problem for existing iPhone owners but it was still accused of failing to address the fact people who had already upgraded were left out of pocket or inconvenienced.

In a bid to bring the matter to a close, and in part because of the cost of ongoing litigation, Apple this week proposed a settlement figure which is expected to cost the company up to $500 million but could be as low as $310 million.

This money will be used to compensate those customers who gave evidence in court for the class-action suit in the first instance, with each receiving $3,500. Those customers named in the filing but who didn't testify will receive $1,500 each. The remaining money will then be divided between US customers who owned iPhone 6, 6 Plus, 6s, 6s Plus, 7, 7 Plus, and SE devices at the time the claim was made.

According to the filing, affected phones needed to be running iOS 10.2.1 or later in the case of the older models, and iOS 11.2 or later in the case of the iPhone 7 and 7 Plus, as long as the software was installed December 21, 2017.

The lawyers will also ask the court to grant them $93m in "reasonable attorneys' fees", which will also need to be taken from the settlement pot, plus a further $1.5m in expenses.

This is likely to equate to just $25 (£20) for each affected user, after all of the fees and charges are accounted for, depending on how many claims are made and what the agreed settlement figure is.