"Fetch TV's new generation of STB's (the Mini and Mighty) support the latest generation of compression technology - HEVC. We are now able to match, and in many cases, exceed the video quality of more traditional delivery networks," said CEO Scott Lorson.
The list of channels set to receive the upgrade include National Geographic, National Geographic Wild, BBC First, Universal Channel, SyFy, Travel Channel, HGTV, Food Network, BBC Knowledge, BBC World News and CNN.
The above will now broadcast at 3.8Mbps - approximately triple the quality of the previous standard.
Previously, only sports channels ESPN, ESPN 2, EPL Channels and beIN Sports were broadcast at the higher bit-rate.
The company says further improvements to the service are still to come within the next 60 days.
Fetch TV has been previously understood to be closing in on a subscriber-base of 600,000.
"Not long ago, streaming services delivered over IP were considered poor cousins to those delivered terrestrially and via satellite. How quickly things have changed" Lorson remarked.
Last year, Fetch TV was one of the first STBs in the world to support 4K viewing of Netflix.
Lorson says they are currently "in-talks" to pursue the same support for Australian streaming player Stan, who announced 4K content would arrive later in 2017.
"We plan to expand our 4K offering in the future, and are working with the content providers to introduce 4K for movies and TV show rentals," he said.