curl --request POST \
  --url https://demo.onlinebillingform.com/api/v1/vpn/servers/update \
  --header 'Content-Type: application/x-www-form-urlencoded' \
  --header 'token: <api-key>' \
  --data id=8 \
  --data server_name=UK5 \
  --data ip_address=IPAddress \
  --data ssh_port=22 \
  --data ssh_password=Password \
  --data ssh_username=root \
  --data max_connection=0 \
  --data country_id=1 \
  --data vpn_type=openVPN \
  --data 'ssh_password_current=Current Password'

{
  "success": true,
  "message": "Server: 8 updated successfully"
}