Hi - PowerPath/VE 6.1 is qualified against ESXi 6.5  You'll need to query against the E-Lab Navigator for your specific configuration (array, operating environment, HBA) to verify compatibility in your environment.  Bob Lonadier  PowerPath Product Manager
From what I can tell, PowerPath/VE 6.1 only supports the latest ESXi 6.0 (Update 2).  Does anyone know if/when a new version is coming out that will support ESXi 6.5?
[Solved] PowerPath/VE for VMware ESXi 6.5