I was just reading this blog.
Decoding the vCenter Server Lifecycle: Update and Versioning Explained - VMware vSphere Blog
It is coincidental, because I will be starting to upgrade to v6.5 U3 this week. Our vCenters are currently in ELM with 4 PSCs. We are mixed at v6.5 U1 and v6.5U2.
So it seems reading this I have to upgrade the v6.5 U1 to U2 first, and then apply the last U2 patch. And then upgrade to U3? And the v6.5U2 I need to patch the last U2 patch and then apply U3?
I could have sworn I have not done this before and jumped around in earlier releases. Thank you.