I thought the releases with even numbers 3.0.16, 3.0.18 are suitable for live systems, and the odd numbers 3.0.17.X are for testing?!
So what are 3.0.18.1/2/3/5 for?
In the activities is written "RC may used live"
What will come after 3.0.18.X?
Is 3.0.18 the official / latest version for live systems?
VM3.0.18 is considered to be stable for live sites - https://virtuemart.net/news/latest-news/477-release-of-3-0-18-connecting-the-loose-ends
But as the last in the VM3.0 series there are a few improvements & fixes still being added, hence the sub-releases which many are already using on live sites.