This doesn't help me, because my travel to Switzerland isn't until Sept. of next year, but there's an upcoming promo for the Swiss Travel Pass and Swiss Travel Pass Flex. I thought I'd pass this info along to others.
If you buy your pass in July of 2021, you get a 25% discount. It appears that you can pick any start date up to 11 months in the future, and can cancel and get a refund until 1 day prior to travel. This appears to mean, for example, that if you want a pass to start on June 15, 2022, you can buy it on July 1 through 15 of this year and save 25%. However, don't rely on that example. I can't see all the details yet since it's just an "upcoming" promo. I found about it through the website of MySwissAlps.com.