The ones I wrote certainly didn't require v=1 to come first. ;-)
But you're right: there's probably cause to be concerned.
On 2/8/18, 10:08 AM, "ietf-dkim on behalf of John R. Levine"
<ietf-dkim-bounces(_at_)mipassoc(_dot_)org on behalf of
> "v=1" doesn't have to come first. It just usually does. I think there
> a version of RFC4871 that did that, but then when challenged we couldn't
> come up with a good reason to keep it that way.
I wonder how many DKIM libraries will accept a signature where it doesn't.
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