It used to be a quarterly or annual payment.
The new way is that you can select to have it paid to the centre to reduce your gap fee, or you can have it paid to yourself.
If you are enrolled in online service, i think it may show the payments that have been made.

FWIW I have had several parents change over after June 17th or whatever the cut off was - FAO had sent out letters saying they wouldn't change it, and maybe this far into the first quarter they won't, but right at the start i had quite a few switch... (that said it took a few weeks for each of those families to update properly in CCMS)