Samsung Electronics is on an update rolling spree for its handsets for the last couple of weeks. Today the Samsung GALAXY S II GT-I9100P receives Android 4.1.2 JellyBean firmware upgrade build JZO54K. Galaxy S2 users can upgrade via Samsung Kies software tool, some of you might get the update over the air. Look for notifications.
After the upgrade process is finished the new build should be JZO54K I9100XWLS8. Make sure you have plenty battery left because this is a major software update.