There's been a lot of chatter lately about the adoption rate of iOS 8, but the reason might lie in the phone's storage capacity.

iOS 8 adoption has increased just 1% since Apple last published stats on the operating system.

Some have speculated that the reason for the slow adoption rate might be because of the broken update that Apple pushed out last month, which turned some people's phones into bricks.

But Apple writer John Gruber points out that there might be an even simpler reason: In order to update to iOS 8 over the air, phones needed to have at least 5GB of storage space available.

Over-the-air updates require a lot of storage space, even though the update itself is only usually 1GB. That's because the update is shuffling around files in the background, and needs the free space to do that.

People don't know that there are ways to back up photos or apps to make more room on the phone. And even if they do know about those tricks, it's still a pain and requires a lot of time to sift through various settings.

The 16GB version of the iPhone 5 was the biggest seller, IDC researcher Ramon Llamas told Computerworld. And he expects the same to be true with the iPhone 6. Not least of which because there's a $100 difference between the storage capacities. For most people, 16GB is enough — until it comes time to update the phone.

"This is a serious problem for Apple, because all those 16 GB devices (let alone the 8 GB ones) aren’t going to suddenly gain more free storage space on their own," Gruber writes. "A lot of these devices might never get updated to iOS 8, but would if the OTA software worked. Unless they can rejigger the OTA software update to require less free space, iOS 8’s adoption rate might lag permanently."