Both Samsung and Apple are rumored to be developing "slim" versions of their next generation smartphones that could introduce new problems.

There's a lot riding on Apple's plans for the iPhone in 2025. At a time when consumers are holding onto their phones for longer periods of time, it's harder than ever to entice iPhone users to upgrade. According to a CNET survey in partnership with YouGov, 44% of smartphone owners only buy a new phone when their current one needs replacing.

The iPhone business, which accounts for around half of Apple’s overall revenue, is in a sales slump following years of mostly incremental upgrades to its devices.