After a 6-year hiatus following a partnership with Samsung for HDR10+, Amazon Prime Video has once again started to offer content in the Dolby Vision HDR format.
In 2016, Amazon announced its first series in Dolby Vision, one of the two premium HDR formats. The following year Amazon struck a deal with Samsung to stream content in HDR10+, the other premium format, and as a consequence Dolby Vision was out of the picture for new titles.
Amazon appears to be warming up to Dolby Vision yet again. With the release of The Rings of Power, Amazon has for the first time in six years released a new title in Dolby's HDR video format. It has also gone back and added Dolby Vision support to The Wheel of Time. In addition, Jack Ryan also available in the format.
At this time, Dolby Vision is supported in the new Amazon Prime Video app on compatible FireTV devices and Smart TVs from brands such as LG and Philips. The Prime Video app must be updated to the latest version. It is not yet supported on Apple TV 4K. Amazon has not provided a list of compatible models.

The Rings of Power is available in Dolby Vision on Prime Video. Screenshot: FlatpanelsHD
HDR10+ and Dolby Vision
The decision to offer Dolby Vision once again does not appear to have affected Amazon's plans for HDR10+, meaning that Prime Video offers content in three HDR formats; the base HDR10 format and both of the premium HDR10+ and Dolby Vision formats.
The company has not commented publicly on the matter but it is worth noting that the two recent additions in Dolby Vision on Prime Video also carry Dolby Atmos audio. Dolby obviously has some leverage due to its strong position in audio.
Amazon is not the first company to change its mind regarding HDR10+ exclusivity. Philips initially shunned Dolby Vision in favor of HDR10+ but later added Dolby Vision support. 20th Century Fox formed the HDR10+ alliance with Samsung and Panasonic but later abandoned HDR10+ in favor of Dolby Vision after Disney had acquired the studio. Of the major players, Samsung is now the lone holdout with its insistence not to support Dolby Vision (it did add Dolby Atmos to its 2022 TVs, though).
HDR10+ and Dolby Vision are both software-based and can peacefully coexisting in TVs and media players as well as on streaming services and discs.
- Source: Amazon via AFTVnews, 4KFilme