Hi, it's totally supported to use MA 5.0.1 with ePO 5.3.0.
It's on page 1 of the MA 5.0.1 release notes in the grey box:
"McAfee Agent 5.0.1 can be used only with McAfee ePO server 5.1.1 or later. You can manage previous
versions of McAfee Agent with the 5.0.1 extension, but previous versions of the Agent extensions
cannot manage McAfee Agent 5.0.1 clients."
Please also see:
McAfee Agent 5.0.1 compatible products