[Koha] Koha 1.2.3...

Hello Everyone, I need to upgrade my Koha version 1.2.2 to the newest version, what I need to do? I understand the version I am using is the old one that doesn’t give an overdue report, which version 1.2.3 gives. Furthermore, it doesn’t record LC class mark. By the way, does the new or newest version store LC class mark? If yes, could someone please lead me to these useful features? Thanks, Anthony Blackie Librarian