dave@Mobius:~$ sudo apt update
[sudo] password for dave: 
Ign http://dl.google.com stable InRelease
Hit http://ppa.launchpad.net wily InRelease                                                              
Hit http://gb.archive.ubuntu.com wily InRelease                                                          
Hit http://dl.google.com stable Release.gpg    
Hit http://dl.google.com stable Release                                
Hit http://ppa.launchpad.net wily/main amd64 Packages                 
Hit http://gb.archive.ubuntu.com wily-updates InRelease
Hit http://dl.google.com stable/main amd64 Packages                                                          
Hit http://gb.archive.ubuntu.com wily-backports InRelease            
Hit http://ppa.launchpad.net wily/main i386 Packages                                          
Hit http://gb.archive.ubuntu.com wily-security InRelease                                                     
Hit http://ppa.launchpad.net wily/main Translation-en                                         
Hit http://gb.archive.ubuntu.com wily/main Sources                   
Hit http://gb.archive.ubuntu.com wily/restricted Sources     
Hit http://gb.archive.ubuntu.com wily/multiverse Sources      
Hit http://gb.archive.ubuntu.com wily/universe Sources        
Hit http://gb.archive.ubuntu.com wily/main amd64 Packages     
Hit http://gb.archive.ubuntu.com wily/restricted amd64 Packages
Hit http://gb.archive.ubuntu.com wily/multiverse amd64 Packages
Ign http://dl.google.com stable/main Translation-en_GB
Hit http://gb.archive.ubuntu.com wily/universe amd64 Packages
Hit http://gb.archive.ubuntu.com wily/main i386 Packages
Ign http://dl.google.com stable/main Translation-en
Hit http://gb.archive.ubuntu.com wily/restricted i386 Packages
Hit http://gb.archive.ubuntu.com wily/multiverse i386 Packages
Hit http://gb.archive.ubuntu.com wily/universe i386 Packages
Hit http://gb.archive.ubuntu.com wily/main Translation-en_GB
Hit http://gb.archive.ubuntu.com wily/main Translation-en
Hit http://gb.archive.ubuntu.com wily/multiverse Translation-en_GB
Hit http://gb.archive.ubuntu.com wily/multiverse Translation-en
Hit http://gb.archive.ubuntu.com wily/restricted Translation-en_GB
Hit http://gb.archive.ubuntu.com wily/restricted Translation-en
Hit http://gb.archive.ubuntu.com wily/universe Translation-en_GB
Hit http://gb.archive.ubuntu.com wily/universe Translation-en
Hit http://gb.archive.ubuntu.com wily-updates/main Sources
Hit http://gb.archive.ubuntu.com wily-updates/restricted Sources
Hit http://gb.archive.ubuntu.com wily-updates/multiverse Sources
Hit http://gb.archive.ubuntu.com wily-updates/universe Sources
Hit http://gb.archive.ubuntu.com wily-updates/main amd64 Packages
Hit http://gb.archive.ubuntu.com wily-updates/restricted amd64 Packages
Hit http://gb.archive.ubuntu.com wily-updates/multiverse amd64 Packages
Hit http://gb.archive.ubuntu.com wily-updates/universe amd64 Packages
Hit http://gb.archive.ubuntu.com wily-updates/main i386 Packages
Hit http://gb.archive.ubuntu.com wily-updates/restricted i386 Packages
Hit http://gb.archive.ubuntu.com wily-updates/multiverse i386 Packages
Hit http://gb.archive.ubuntu.com wily-updates/universe i386 Packages
Hit http://gb.archive.ubuntu.com wily-updates/main Translation-en
Hit http://gb.archive.ubuntu.com wily-updates/multiverse Translation-en
Hit http://gb.archive.ubuntu.com wily-updates/restricted Translation-en
Hit http://gb.archive.ubuntu.com wily-updates/universe Translation-en
Hit http://gb.archive.ubuntu.com wily-backports/main Sources
Hit http://gb.archive.ubuntu.com wily-backports/restricted Sources
Hit http://gb.archive.ubuntu.com wily-backports/universe Sources
Hit http://gb.archive.ubuntu.com wily-backports/multiverse Sources
Hit http://gb.archive.ubuntu.com wily-backports/main amd64 Packages
Hit http://gb.archive.ubuntu.com wily-backports/restricted amd64 Packages
Hit http://gb.archive.ubuntu.com wily-backports/universe amd64 Packages
Hit http://gb.archive.ubuntu.com wily-backports/multiverse amd64 Packages
Hit http://gb.archive.ubuntu.com wily-backports/main i386 Packages
Hit http://gb.archive.ubuntu.com wily-backports/restricted i386 Packages
Hit http://gb.archive.ubuntu.com wily-backports/universe i386 Packages
Hit http://gb.archive.ubuntu.com wily-backports/multiverse i386 Packages
Hit http://gb.archive.ubuntu.com wily-backports/main Translation-en
Hit http://gb.archive.ubuntu.com wily-backports/multiverse Translation-en
Hit http://gb.archive.ubuntu.com wily-backports/restricted Translation-en
Hit http://gb.archive.ubuntu.com wily-backports/universe Translation-en
Hit http://gb.archive.ubuntu.com wily-security/main Sources
Hit http://gb.archive.ubuntu.com wily-security/restricted Sources
Hit http://gb.archive.ubuntu.com wily-security/multiverse Sources
Hit http://gb.archive.ubuntu.com wily-security/universe Sources
Hit http://gb.archive.ubuntu.com wily-security/main amd64 Packages
Hit http://gb.archive.ubuntu.com wily-security/restricted amd64 Packages
Hit http://gb.archive.ubuntu.com wily-security/multiverse amd64 Packages
Hit http://gb.archive.ubuntu.com wily-security/universe amd64 Packages
Hit http://gb.archive.ubuntu.com wily-security/main i386 Packages
Hit http://gb.archive.ubuntu.com wily-security/restricted i386 Packages
Hit http://gb.archive.ubuntu.com wily-security/multiverse i386 Packages
Hit http://gb.archive.ubuntu.com wily-security/universe i386 Packages
Hit http://gb.archive.ubuntu.com wily-security/main Translation-en
Hit http://gb.archive.ubuntu.com wily-security/multiverse Translation-en
Hit http://gb.archive.ubuntu.com wily-security/restricted Translation-en
Hit http://gb.archive.ubuntu.com wily-security/universe Translation-en
Reading package lists... Done
Building dependency tree       
Reading state information... Done
3 packages can be upgraded. Run 'apt list --upgradable' to see them.
dave@Mobius:~$ sudo do-release-upgrade
Checking for a new Ubuntu release
No new release found
dave@Mobius:~$ lsb_release -d
Description:	Ubuntu 15.10
dave@Mobius:~$