The biggest codepoint in Unicode fits into 4 bytes of UTF-8. UTF-8 would allow up to 6 bytes, but those codepoints are not in use currently. If they ever become

The biggest codepoint in Unicode fits into 4 bytes of UTF-8. UTF-8 would allow up to 6 bytes, but those codepoints are not in use currently. If they ever become in use, yes, you'd probably need a new character set again. But then a lot more things will break, as higher codepoints would be incompatible with UTF-16 also.