Buying tickets for the Colosseum (Rome)

Hi there,

I’m heading to Rome soon and wanted to book my tickets for the Colosseum.

I found the official site, but I don’t understand when it’s possible to make a reservation.

Apparently, it’s 30 days in advance for the underground tour since everything is already booked up for the next 30 days...

But what about the Colosseum + Arena visit? The site shows tickets for the next 7 days, but nothing after that. Are tickets released just a week in advance for this combo, not 30 days?

Thanks for any clarification! !