Serviio

Is this feature in yet? lately i'm using plex cause of 4K HDR support.
But plex always buffers or hangs while playing big mkv files while my PC is powerful enough to do it smoothly.

I never had issues with Serviio so i want to come back.

4K support depends on your player. Serviio has no problem streaming H.264 or H.265 4K content. I've streamed 4K with my Roku 4 and Ultra for quite some time. I have a number of 4K demo videos downloaded from http://demo-uhd3d.com/. No issues with HDR content either.

I'Have a Sony Bravia but with Roku 4k doesn't work, my tv works fine with play station 3 profile but I Hven't 4k streeming

What Roku player, and which profile are you using? The default Roku profile isn't the correct one for the 4K players. There's a specific profile for Roku 4K players, and another for the 4K TVs. There's also a new profile for the latest 4K players that now support MPEG-2 video. In theory, that should be all the Roku 4K players except for the Roku 4.