Licenses can be freely moved as follows

• Fusion 12 (player or Pro) licenses can be used on Fusion 12 or Workstation 16
• Workstation 16 (player or Pro) licenses can be used on Fusion 12 or Workstation 16
• Fusion 13 (player or Pro) licenses can be used on Fusion 13 or Workstation 17
• Workstation 17 (player or Pro) licenses can be used on Fusion 13 or Workstation 17

Earlier version licenses are not interchangeable between Fusion and Workstation.