I think, for now, we can't exclude 5.5 or 5.0. 5.5 at least. Thing is, a lot of corporate environments have Windows 2000, with 5.0... and you can't upgrade. Period. No question, no wonder - it won't happen. And, these offices are often against upgrading to XP; hence we should really keep 5.x. I personally also want to keep 4.0...
Internet Explorer 4.0 isn't that bad, actually, with support. But it has its issues.
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