It took a long time, but Apple will finally support 4K HDR when the fifth generation of the Apple TV rolls out.

Developer Guilherme Rambo tweeted a reference to the display mode when he tinkered with the HomePod firmware. As pointed out by another user, the new Apple TV will also support three HDR formats: Dolby, HDR10 and Hybrid Log Gamma.

The development further fuels the rumors that 4K support is inevitable for the Apple TV.

Last month, customers found out that their recent iTunes purchases had the option for a 4K and HDR format. Downloaded files, however, were just in standard high-definition, and the 4K and HDR option was limited to some regions.

Earlier this year, it was reported that Apple was testing an Apple TV capable of streaming Ultra HD 4K video. The project was codenamed "J105," according to Bloomberg.

The hiring of former Amazon Fire TV unit chief Timothy D. Twerdhal is also an indicator that the 4K compatibility will soon hit Apple TV.

Bloomberg reported that Twerdhal's arrival coincides with Apple finally releasing an Apple TV capable of 4K. It is reported that the product, codenamed "J105" will support ultra-high-definition 4K with more vivid colors.

Apple TV's move to 4K is long overdue. Rival streaming devices like Amazon and built-in smart TV systems has been supporting 4K and HDR. Even streaming giant Netlfix is streaming its new series in 4k to compatible TV sets and the Xbox One S is also capable of reading 4K Blu-ray formats.

Two Apple products currently support 4K display; the 21.5 inch iMac with Retina 4K and the 27-inch iMac with Retina 5K display.

The Apple TV Fifth Gen is expected to be revealed at the end of the year together with the latest iPhone.