The Apple Watch may have a mysterious port that could solve its biggest problem

When the Apple Watch goes on sale, it will start at $349 and could cost $10,000 for the premium gold version.

That's a lot to spend on something that could be obsolete within a couple years.

But a mysterious port on the inside of the "bottom" strap connector could be the key to extending the Apple Watch's life, according to TechCrunch's Matthew Panzarino.

The 6-dot port is only being used for diagnostic tests now, but it could be used by third-party band makers down the road.

Third-party bands could be as common as third-party iPhone cases down the road. Band manufacturers could use the port to incorporate new features or extend the watch's battery life.

That means you could update your Apple Watch by purchasing a new band instead of a new watch for a fraction of the cost.

Panzarino says the port is only on Apple Watches being tested by employees. It's possible it might not be on the models that go on sale soon.

However, 9to5Mac says the mystery port won't be on models that get shipped. It's just a Lightning port that is used for testing, according to this report.

But if it does end up on the final product, it could be a gateway into Apple Watch customization and a cost-effective way to keep devices up to date.

Either way, we'll probably find out more at Apple's upcoming event on Monday.