See "What's inside VMware vSphere 6.5 Update 1" by Florian Grehl at virten.net featuring historical ESX/ESXi graph
Sometimes there's a post that is so perfect as it is that I just have to call it out, hoping to extend the readership of the author's source article. Simple, elegant, and to the point, not exactly my strengths. I therefore present to you, with little words to say other than "read this" and "enjoy"!
- What's inside VMware vSphere 6.5 Update 1
Jul 28 2017 by Florian Grehl at Virten.net, highlights/excerpt:vCenter Server 6.5 U1 - What's new

Teaser - the refreshed Clarity UI evident in the vSphere Client [HTML5]. - Upgrade from vCenter 6.0 U3: vCenter Server 6.5 Update 1 supports upgrades and migrations from vCenter Server 6.0 Update 3 and above to vCenter Server 6.5 Update 1.
- HTML5 Client with 90% feature support: The HTML5-based vSphere Client now can support up to 90% of general workflows.
- General Support until November 2021: VMware has extended the general support for vSphere 6.5 for a full 5 years. This means that support for vSphere 6.5 will now end November 15, 2021.

See also at TinkerTry
-
How to easily update your VMware vCenter Server Appliance from 6.5.x to 6.5 Update 1 (VCSA 6.5 U1)
Jul 28 2017 -
How to easily update your VMware Hypervisor from 6.5.x to 6.5 Update 1 (ESXi 6.5 U1)
Jul 28 2017 - vSphere 6.5 Core Storage white paper - one home virtualization lab enthusiast's perspective
Dec 07 2016
See also
- VMware Product Release Tracker (vTracker)
by Florian Grehl at Virten.net featuring his famous vTracker RSS Feed.







These systems still work great for many even 9+ years later, mine included, even with (unsupported) vSphere 8 and Windows 11 Version 21H2. But unless you added the optional TPM module, it may be the end of the line as far as repurposing them for running the latest Windows 11 Version 24H2 and beyond.