Updating the minimum length of stay in your listing's availability settings will be applied to all future dates. If you want to update the minimum length of stay for specific dates only, you can do this in the Calendar by clicking on the date range for the relevant listing. See here for more information.
Important:
Guesty For Hosts availability settings are synched with Booking.com but not with Vrbo. To understand where different listing data items are managed for your Vrbo connection, see this article.