I’ve been searching for a way to show a calendar to respondents that only allows them to select a date within the previous 12 months of the current date. Anything past 12 months would not appear for them. If this isn’t possible, we could also have a custom prompt that closes the survey if they were to pick a date from say, 13 or 14 months ago (from current date). I would greatly appreciate any help. Thank you!

flatpickr has options to accomplish your requirements. Search the Community for implementation details.

Modify Calendar to only show 12 months past current date

Modify Calendar to only show 12 months past current date | Experience Community