After you have installed PAF 5, just look for where you your PAF 4 data stored. PAF 5 will "convert" this data to its required format. However, after that you will still have your PAF 4 data intact and can continue to use it in PAF 4. PAF 5 will now have the same (converted) data ready for its use. You just decide which one to use - 5, 4 or both.