The latest firmware update seems to have had no positive effect on rendering special characters or to even manage extended ASCII. That is to say, it cannot interpret characters from West European languages.
It's not too much to ask for the capability to render the commonest languages in the Roku interface, independent of the the apps associated with a particular "channel." It shouldn't be a problem to render in UTF8.
It looks like it is now interpreting UTF-8 encoded strings, which is good and bad. My channel was converting UTF-8 to single bytes (greater than 127) to use with its own font and now that's broken. It looks like if I take out my UTF-8 conversion things display properly (at least in my limited testing). It would have been nice to have gotten a heads up on this.
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It's not like Roku has unlimited resources. They'd probably do better focusing on, say, Australia than Russia for expansion. It's not possible to expand everywhere all at once. You have to take one step at a time.