Jerryt wrote on Jul 3^rd, 2022 at 2:06pm:

Must you purchase P3Dv5 from Lockheed before purchasing Captain Sim B757 version?

No. However....
1. If you have P3Dv4, you can use the 64bit version in that sim until you buy P3Dv5.
2. There is a 32bit version for FSX/FSX-SE/P3Dv3, but if you buy that, then move to P3Dv4, or P3Dv5, you will need to buy the 64bit version for either of those sims.
3. If you don't have P3Dv4, or P3Dv5, then you won't be able to use it until you buy one of them, so it would be better to wait until you do (unless the 757 Captain III is on special).