PayPal callbacks

Before I migrate my domain to CloudFlare, I am concerned that callbacks from PayPal to my server will be flagged as high volume and be blocked/challenged if I don’t whitelist them.

Does anyone have any insight into whether this will be a problem or not?

e.g.

  1. Has CF already whitelisted all the PayPal source IP addresses for callbacks? (BTW - I tried to find that list and failed and it could change anyway)
  2. Anybody got any advice?