Apple is reportedly developing a new iPhone charging accessory in the form of a battery pack that magnetically attaches to the rear of the device using MagSafe, Bloomberg reports. Although some prototypes have a rubber exterior, the battery pack isn’t thought to act as a protective case like previous iPhone battery accessories from Apple. Alongside details of the new battery case, Bloomberg also notes that the iPhone lineup is unlikely to receive support for reverse wireless charging anytime soon.

The battery pack accessory is thought to have been in development for at least a year, but it’s reportedly faced development issues relating to the iPhone’s software thinking that the pack is overheating. Bloomberg notes that Apple is cautious about announcing charging accessories, after it was forced to cancel its AirPower charging mat in 2019, a year and a half after it was first announced. Development problems could mean that the new battery pack accessory is delayed or even scrapped.

The charging pack would be the latest in Apple’s lineup of iPhone 12 MagSafe accessories, which attach onto the back of the phone with the assistance of an embedded circle of magnets. Previous accessories have included wall chargers, as well as magnetically attaching wallets. MagSafe is said to be returning to Apple’s laptops as well, only with a connector reminiscent of the old pill-shaped design.

Rumors of the new battery pack first emerged after a reference to it was found in code in the iOS 14.5 beta, MacRumors reported earlier this week. Bloomberg notes that the reference has subsequently been removed.

As well as the new battery pack, Apple is reportedly interested in allowing its devices to charge one another. Bloomberg notes that it had planned for its 2019 iPhone lineup to be able to wirelessly charge AirPods, but the plans were later scrapped. The functionality is “unlikely in the near future,” according to Bloomberg.

Other accessory manufacturers are already attempting to offer similar functionality to the rumored MagSafe battery pack. 9to5Mac reported on one such pack late last year, which was being sold on Alibaba and Aliexpress under a variety of names.