Which generation? 

The server Model is NX-1050 not have a generation in information

 "model_string": "NX-1050"

nutanix@NTNX-14SMXXXXXXX-B-CVM_IPAddr:~$ allssh cat /etc/nutanix/hardware_config.json | grep "model_string"
    "model_string": "NX-1050",
    "model_string": "NX-1050",
    "model_string": "NX-1050",
 

Got it (in your first post you where typing NX-1065). 

The NX-1050 is EOL and new versions will not be tested against EOL hardware, so the NX-1050 is removed from the HCL. 

But that doesn't mean it cannot work. You can try to install/foundation the cluster with the version you want, probably it will work, though. But there is no support off course and if it doenst work you must refoundation to the latest working version to have a dev/test cluster. 

However again, it is dev/test so try ;) 

Apologize for mistake in my first post. Currently the cluster is running with AOS 5.15.7 I will try upgrade to AOS 5.20.x. Thank you for your advise.

According to this post, it should work: NX-1050 Compatibility matrix

Upgrade will not works as its failed on pre-checks.

You can refoundation with the latest AOS version. 

EOL hardware is not qualified for new software, it could support critical security updates.

@apiwat_sang

You can definitely do this. At least it works for me on old hardware.

Download the AOS tar.gz and put it on a CVM in a directory you create within /home/nutanix. For example, create /home/nutanix/upgrd, put it in there with WinSCP, or scp. Then SSH to the CVM and do:

$ cd /home/nutanix/upgrd

$ tar xvf nutanix_installer_package-release…..tar.gz

$ /home/nutanix/upgrd/install/bin/cluster --ignore_preupgrade_tests -i /home/nutanix/upgrd/install upgrade

Edit: this might not be right. let me check and get back to you. I have to find the exact command.