In this window, to the left, a table of the current accounting year's all periods is shown. The current period is marked with an arrow in the period column. Other columns in the left portion are Start, End, Open, Closed and Locked.
At the very bottom there are two buttons: Switch period and Undo period switch.
In the right portion, the number of edited vouchers of each voucher number series is shown for the selected period. There is also a checkbox where individual number series of an open period can be blocked for accounting. The other columns in the right portion show by whom the voucher series were blocked and what date it was performed.