[belorn]

Could you explain what fixed/immune means? Is it only the confusable characters, ie characters that are visually identical or near-identical to latin characters, that is getting the punycode treatment?

[H4CK3RM4N]

I think IE and Safari just don't support Unicode in domains.

[paulddraper]

I'm not sure the nature of Chrome's fix, but IE and Safari don't support punycode.