Indeed images are not automatically build currently. However, every image is updated automatically on first boot with increment migration steps, where required. But yes, I'll update the ROCKPro64 image now, as it is quite old, to prevent the unnecessary large amount APT package upgrades.
EDIT: New image has been uploaded: https://dietpi.com/downloads/images/Diet...-Buster.7z
EDIT: New image has been uploaded: https://dietpi.com/downloads/images/Diet...-Buster.7z