Oracle says it will start issuing quarterly security patches in January, slowing down a schedule the database and business software company says caught some customers unaware. The new patch schedule comes just months after Oracle said it would issue security updates each month. The schedule will let customers plan in advance for patches, rather than react to surprise alerts, Oracle says. It also could help companies avoid so-called "blackout" days at the end of quarters, when many companies don't update systems because they're closing their books. Microsoft, SAP, and Computer Associates also adhere to regular patch schedules.