When you make a change to the device profile you need to stop your Mezzmo Media server and start it again so that the new profile changes are loaded. We have the Roku 4k profile in the current version of Mezzmo which supports h265, dts and matroska. The problem with Roku devices is that it is difficult to determine the model from the Mezzmo server and each Roku supports different formats depending upon the age of the device. For newer Roku devices you should use the 4k profile.