Whenever it's been offered in the past, you could book it as soon as it was open for booking, no matter what date you wanted your package.
A number of DIS posters who have called in are being told by CMs on the dining line that this year it is going to be 90 days from the date you want it, like everything else.
No way to know if that's true until they start booking. However, if it is true, there is no need for the packages to be released in June the way they were last year. 90 days from November would be sometime in August.