I had some trouble recreating this one but here goes: To recreate: 1. In your koha-conf.xml set the timezone to: <timezone></timezone> 2. Enable bookings and make an item or itemtype bookable. 3. Place a booking and have a look at the start_date and end_date in the DB: select start_date, end_date from bookings; 4. This might look something like: 2025-05-13 02:00:00 | 2025-05-15 01:59:59 So depending on your timezone and time of day the booking end_date might creep into the next day which causes confusion.