I don't think there's been a rule change, it's just in the past some people have frowned on DIYing sportives because they're grumpy bastards rather than there being any specific rule against them*. In practice you can submit anything and you're unlikely to be rejected.
(* There is still a rule on the books that bans drafting of people who aren't also entered into the same audax, which would disqualify many DIYs, were anyone to actually care, which they don't)
I don't think there's been a rule change, it's just in the past some people have frowned on DIYing sportives because they're grumpy bastards rather than there being any specific rule against them*. In practice you can submit anything and you're unlikely to be rejected.
(* There is still a rule on the books that bans drafting of people who aren't also entered into the same audax, which would disqualify many DIYs, were anyone to actually care, which they don't)