Hi @Thomas_Giloy,
You can find the release notes for 1.6 here:
The Nucleus automatically updates to Roon’s latest version unless you have this disabled in Roon Settings -> About -> Cogwheel Icon but I would highly suggest leaving it to automatically update so that your Core can receive any critical fixes as soon as they’re published.
The update is completed for your Nucleus, it usually takes anywhere between 5-10 minutes to perform an update and we don’t release these too often, you can check how often they have been released in the past by navigating to our Release Notes Section.
Thanks,
Noris