There's no need to panic when you see this precheck failure
VMware Aria Automation needs extra bit of memory compared to previous versions for Medium sized nodes.
This will only be seen on Medium sized appliances and not for Extra Large sized appliances. Keep this in mind.
The new requirement is 54 GB
That's what is stated in the precheck failure
What should you do?
Power Off VMware Aria Automation using Day-2 action available on the product
Delete any snapshots available on the VMware Aria Automation appliances, as you cannot increase the memory to the desired value if they are present
Once snapshots are deleted, go ahead and increase the value to the desired 54 GB on all of the appliances (1 applinace if it is a standard deployment, 3 if it is a clustered deployment)
Once the appliances are reconfigured, now power them back on using Day-2 action in VMware Aria Suite Lifecycle for VMware Aria Automation
Wait for the task to complete.
Once done, now the precheck should succeed and then your allowed to upgrade to VMware Aria Automation 8.16.2
Another option is to perform a vertical scale-up, but that would only give you an option to choose extra large sizing which would be way more than you need.