Using Channels on ATV for a long time and just lived with the fact that some Channel names containing german Umlauts were wrong and got no EPG data... after installing HD Homerun app on IPad one day I recognised it had the same broken names... and already knew my channels without extensive search...
Reading up a bit... I found a Post that stated: Scanning for Channel Names in their windows app would fix that... ok lets try that ... download HD Homerund windows app search for channels there... it will find correct names and write the config to their server...
Channels then picks them up right away without problems...
Thought I share that here if anybody else is searching for a solution... If seen this remark regarding Umlauts in the AppStore but not here... hope that helps somebody...