Ferry Ticket Availability

Hello,
Do you know how far out tickets become available for purchase on CKS's website?
It seems like they only allow tickets to be purchased a few weeks in advance of the travel date, or possibly only allow tickets to be sold for travel within the current month, but I'm not completely certain.

For example, right now (Dec 12, 2023) I only see the option to purchase tickets from Shekou to SkyPier out through Dec 31.

Thanks in advance!