It's hard to believe the "new" Apple TV is already a couple years old.

But, like clockwork, Apple is already developing a follow-up to its fourth-generation Apple TV. Dubbed Apple TV 4K by the media, the upcoming set-top box first popped up in February, thanks to a report from Bloomberg. Now, several months later, we've seen more evidence that the fifth-generation Apple TV is coming, and it'll support both 4K content and HDR. Here's everything you need to know.

Apple TV is a "set-top box" device that you can hook up to your TV to access video apps and streaming services. It was originally labeled a hobby device, but by 2015, Apple CEO Tim Cook revealed that 25 million units had been sold. So, in late 2015, it announced a new Apple TV with Siri, a trackpad remote, a new operating system called tvOS, an app store, and two different storage capacities. But it didn't support Ultra HD (4K) content or high-dynamic range (HDR) content.

You can learn more about Apple TV, 4K, and HDR from these guides:

In February 2017, Bloomberg reported that Apple planned to launch a new Apple TV set-top box that supports 4K content, and it could launch as soon as this year, with support for “more vivid colors" (which may refer to support for HDR). Since then, the rumoured device, codenamed J105, has been called Apple TV 4K. But that's not an official name, as Apple hasn't even confirmed its existence.

If you need more proof that it's coming, a new report from MacRumors showed that iTunes in July 2017 began to list movies as supporting 4K and HDR in users’ purchase histories, which suggests that Apple’s digital storefront and maybe even devices may support those videos soon. Right now, you can't download movies in 4K or HDR through iTunes, but they'll appear in your purchased history still.

It's easy to assume Apple has added these tags because it plans to offer 4K and HDR videos sometime in the near future. Apparently these tags are now live for Passengers, Fantastic Beasts, and Where to Find Them.

Apple TV 4K would need a faster processor. The current Apple TV uses the A8 chip, which was launched alongside the iPhone 6 and iPhone 6 Plus in 2014. If Apple announced a new set-top box soon, with support for 4K and HDR, it's safe to assume it would come with newer silicon, maybe even the A10 Fusion, which Apple introduced with the iPhone 7 last autumn. But there's no proof of that yet.

Apple recently seeded the third beta of an upcoming tvOS 11 update to its public beta testing group. Since Apple usually announces new hardware in the autumn for the upcoming holiday season, it’s likely that, if there is a new Apple TV 4K on the horizon, it'll run tvOS 11.

This one is a bit of a stretch, but Apple has been rumoured - for years now - to be working on its own TV streaming service, similar to Netflix. If all the speculation were to be believed, it would be a paid service with fancy features like live TV and cloud-based DVR. Of course, at the same time, there has been a lot of talk about Apple's failed attempts at securing partnership deals.

So, we wouldn't bet on this feature coming to the next Apple TV, but check out this guide to learn more anyway.

As we mentioned, and other reports have noted, Apple usually announces new hardware in the autumn. We may hear about the new Apple TV 4K at the next iPhone event, or maybe shortly after.

Only time will tell. But we'll keep you posted.