Once you have used ZOKRI for more than one quarter, you will have OKRs, Priorities etc in different time periods. To show the items from different quarters / years select the new quarter from the top right.
If you have Continued OKR to the next period, they will be linked and in the details view you can see the history of previous versions of the OKR (see How do I continue / copy OKRs to the next Quarter?)