When you're setting up a package or editing an existing package in the Business Settings > Packages & Gift Certificates page, the package can be set to expire a certain number of days after it is purchased. If you leave this section blank the package will never expire.
Package codes can be redeemed up until their expiration, for appointments taking place anytime in the future. For example, if a package is set to expire after 30 days, then clients can use the code until 30 days after the purchase. But they can book an appointment on your calendar for a date further than 30 days in advance if availability is displaying on your client-scheduler.
Limit Advance Booking
You won't be able to limit the actual dates a client can book, but your scheduling limits will prevent clients from booking too far in the future.
However, if you'd like to limit how far into the future clients can book to coincide with a packages expiration date, head over to the Availability > Scheduling Limits page, and you could limit clients from booking further than 30 days into the future.
Extending the Expiration Date
Extending the expiration date for the entire package will also update all existing codes which haven't been edited.
The expiration date for an individual code can be changed by editing that code and adjusting the date.
To edit an individual package's expiration date, go into the package in the Business Settings > Packages & Gift Certificates page and click the "Edit" button next to the code you'd like to edit. You'll be able to adjust the package's expiration from there!