Jun 2, 2017 - 3:22 AM
I mail this question to firstname.lastname@example.org, got this reply
"Yes, to get the discounted Jungfrau Travel pass fare you would have to use 4 free days on your Swiss Travel Pass Flex."
I think you can buy discounted Jungfrau Travel pass with Flexipass, but that will cost you a lot. I haven't buy Flexipass yet. I'm thinking of buying Flexipass or Half Fare card or both.