[Koha] Upgrade to Koha 18.11 on Ubuntu 16.04

Hi, I have instance of Koha 17.11.05 installed on an Ubuntu 16.04 LTS. I would like to upgrade Koha to the current version 18.11., but I get the error: sudo apt-get install koha-common Reading package lists... Done Building dependency tree Reading state information... Done koha-common is already the newest version (17.11.05-1). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Any idea how resolve this problem please? Many thanks, Karel Matějka -- Sent from: http://koha.1045719.n5.nabble.com/Koha-general-f3047918.html