Hi. And welcome
The answer is yes. But according to some of core developers, the rc2 (yes, we had rc2) is deployed to some of their customers already. And the current updates are only bug fixes. New features are not currently accepted for r4.3
The official source is qubes-udpate repository on Github and its issues. I publish a weekly review newsletter and list the new (testing) updates which would eventually land in stable. You could find it if you search the forum.
Also please consider many updates would be from upstream (Fedora, Debian) rather than Qubes.
We have qubes-vm-update --dry-run for updating vms and sudo qubes-dom0-update --assumeno. You could run hem in dom0 which will just print list of packages available for update.