But there is no better answer.
The feature freeze for the old Windows C# vSphere Client war in 5.5. The introduction of the HostClient starts as a Fling (you should check if there is a newer version).
Later VMware ships the Hostclient together with ESXi as a replacement of the old vSphere Client. The vCenter comes with a flashed Based WebClient which later was replaced with a HTML5 which than was renamed to vSphere Client.
So... if you would spend 500 Bucks for a vSphere Essentials or going the VMUG Adv. road you have the option to deploy a VCSA 7.0u3 to get the latest WebGUI which is also able to manage your old 6.5 Host.
The extended support period of ESX 6.5/6.7 ends in October 2022.
IIRC you could manage a 6.5.0 or u1 with the old C# windows Client. Get it running on a modern windows maybe another challenge.
Regards,
Joerg
