Content-Type: application/x-mpegURL but no charset parameter. The TV defaulted to ISO-8859-1. UTF-8 characters became garbage. He switched to an IPTV Reseller Panel that served Content-Type: application/x-mpegURL; charset=utf-8 and also included a #EXTM3U charset=utf-8 directive in the file. All devices displayed correctly. What actually works is asking about your panel's M3U encoding headers. Most operators find that British IPTV panels either omit charset (bad), include HTTP header (better), or include both HTTP header and M3U directive (best). You want both. You also need to check whether your panel can serve different encodings to different devices. Some devices need UTF-8. Some need ISO-8859-1. Some need Windows-1252. A good panel detects device user agent and serves the appropriate encoding. Some British IPTV panels offer "encoding override" – you can manually set the encoding per customer if auto-detection fails. That's a good fallback. Honestly, the most encoding-robust British IPTV reseller I knew avoided special characters entirely. He renamed "Motörhead" to "Motorhead" and "François" to "Francois". No encoding problems because there were no special characters to mis-encode. The pattern that keeps showing up is that encoding problems are device-specific and hard to debug. Your panel says the file is fine. Most devices agree. But the one customer with the old TV sees garbage. They think your service is broken. Your IPTV Reseller Panel should handle encoding explicitly, not leave it to chance. Test your M3U on a variety of devices. If any show garbled text, your encoding headers need work. Your customers deserve readable channel names on every screen.