Here are the some command to upgrade ESXI , there are many ways to upgrade the ESXi host , here i am sharing command to upgrade ESXI host from the offline bundle.

Nutanix provides one click hypervisor upgrade but if you choice to do one by one still steps are applicable.

copy the files to  ESXI datastore

migrate the running VMs to other host

if Nutanix , shutdown CVM

Place the host in Maintenance mode

ssh ESXI host

esxcli software sources profile list -d /vmfs/volumes/default-container-56642316230438/VMware-ESXi-6.5.0-4564106-depot.zip

(dry-run) to make sure command will work fine

esxcli software profile update -d //vmfs/volumes/default-container-56642316230438/VMware-ESXi-6.5.0-4564106-depot.zip -p ESXi-6.5.0-4564106-standard  –dry-run

now run the command without (dry-run) to start the upgrade

esxcli software profile update -d //vmfs/volumes/default-container-56642316230438/VMware-ESXi-6.5.0-4564106-depot.zip -p ESXi-6.5.0-4564106-standard

upgrade will finish in second and reboot the host

esxcli system version get