我对 OwnCloud 桌面版本的更新有疑问：
teddy@Yoga-2:~$ sudo apt-get update --allow-unauthenticated
[sudo] password for teddy:
Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease
Ign:2 http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_15.10 InRelease
Get:3 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [94,5 kB]
Get:4 http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_15.10 Release [1023 B]
Get:5 http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_15.10 Release.gpg [189 B]
Ign:5 http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_15.10 Release.gpg
Hit:6 http://download.opensuse.org/repositories/isv:/ownCloud:/desktop/Ubuntu_15.10 Packages
Hit:7 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
Get:8 http://archive.ubuntu.com/ubuntu xenial-security InRelease [94,5 kB]
Get:9 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages [242 kB]
Get:10 http://archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages [238 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial-updates/universe amd64 Packages [130 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial-updates/universe i386 Packages [127 kB]
Fetched …