Past shows can be locked down to prevent accidental edits. This is useful for agencies that use show data for accounting purposes.
The "Lock shows"-panel can be accessed from system settings > lock shows and can be used to lock a selection of bookings.
You can select which shows you want to lock using the filters on the left side.
In the right side of the panel the number of affected shows is shown.
When you click the "Lock shows"-button the shows are locked.