The order of upgrades when required is believed to be:
VIP (Heads of State, Government Bodies, or Canto Pop/Movie stars)
CX Diamond Plus
CX Diamond Invitation, Diamond
CX Gold
CX management staff on travel duty
oneworld Emerald
CX staff on duty nominees , other airline staff nominees, CX staff on personal travel
oneworld Sapphire
CX Silver
oneworld Ruby
CX Green
Asia Miles
Non status
When there is op-up happening on certain flight, what order will passenger holding an upgrade voucher have?