This article explains the vSAN firmware version recommendation engine health check in the vSAN Health Service and provides details about why it might report an error.
vSAN's firmware recommendations for Update Manager require that Update Manager is available. The build recommendation engine relies on the VMware Compatibility Guide and VMware release metadata.
This health check verifies that the vSAN cluster meets all dependencies and the firmware recommendations are made correctly.
Note: As of vSAN version 8.0 this test has been depreciated and will no longer be part of the vSAN Health Check.