VMware Cloud on AWS is a managed service that includes managed patching of the VMware SDDC "stack". Part of this stack is vSAN which is a hypervisor native storage solution that is a part of the vSphere hypervisor. VMware Cloud on AWS regularly performs updates on your SDDCs. These updates ensure continuous delivery of new features and bug fixes, and maintain consistent software versions across the SSDC fleet. Upgrades to even-numbered releases of the SDDC software, such as VMC Version 1.10 or 1.12, will be provided to all SDDCs and are mandatory. Odd-numbered releases, such as 1.11 or 1.13, are available only for new SDDC deployments. These optional releases are not available for upgrades. When an SDDC update is upcoming, VMware sends a notification email to you. Typically, this occurs 7 days before a regular update and 1-2 days before an emergency update.
One question I see customers ask is "What version of vSAN is VMware Cloud on AWS running?"
The easy way to check this is to consult with the documentation that specifically exists for Correlating VMware Cloud on AWS with Component Releases.