diff --git a/ESXi/README.md b/ESXi/README.md
index ca916a0..08aea0d 100644
--- a/ESXi/README.md
+++ b/ESXi/README.md
@@ -23,6 +23,15 @@ NOTE: This is an early release and it's possible that certain features may not w
 
 1. **(5 Minutes)** Edit the variables in `DetectionLab/ESXi/Packer/variables.json` to match your ESXi configuration. The `esxi_network_with_dhcp_and_internet` variable refers to any ESXi network that will be able to provide DHCP and internet access to the VM while it's being built in Packer.
 
+Note: As per ESXI 7.x, built-in VNC server has been removed from distribution (https://docs.vmware.com/en/VMware-vSphere/7.0/rn/vsphere-esxi-vcenter-server-70-release-notes.html). If you are using ESXI 7.x, you need to:
+* Upgrade Packer to 1.6.3+, we need to use `vnc_over_websocket` instead of old vnc configuration : [see packer issue](https://github.com/hashicorp/packer/issues/8984), [changelog](https://github.com/hashicorp/packer/blob/master/CHANGELOG.md)
+* Add two config to windows_10_esxi.json, windows_2016_esxi.json, ubuntu1804_esxi.json like this:
+```
+"vnc_over_websocket": true,
+"insecure_connection": true,
+```
+Ref: https://www.virtuallyghetto.com/2020/10/quick-tip-vmware-iso-builder-for-packer-now-supported-with-esxi-7-0.html
+
 2. **(45 Minutes)** From the `DetectionLab/ESXi/Packer` directory, run:
 * `PACKER_CACHE_DIR=../../Packer/packer_cache packer build -var-file variables.json windows_10_esxi.json`
 * `PACKER_CACHE_DIR=../../Packer/packer_cache packer build -var-file variables.json windows_2016_esxi.json`