Upgrade Kubuntu 17.04(zesty) to 17.10(artful arc) - upgrade from 17.10 to 18.04

if you try to update your Kubuntu 17.04, you get error in your terminal, i.e. 404.
" The 17.04 repositories have been closed and withdrawn. That is why you cannot reach them". so to upgrade your 17.04 to 17.10.
you can follow this 17.04 to 17.10

i did following steps to achieve that:

• update the sources list:   ~$ sudo nano /etc/apt/sources.list 

• replace every 'zesty' code name with 'artful' code name. 

• zesty is 17.04 code name and artful is 17.10 code name. 

•  then issue this command at terminal: ~$ sudo apt update | ~$ sudo apt upgrade

• ~$ sudo apt dist-upgrade | sudo do-release-upgrade 

i used 2nd and 4th link as a reference.

rest are easy.
good luck
Useful links:

• http://au.archive.ubuntu.com/ubuntu/ubuntu/ubuntu/dists/ 
• https://help.ubuntu.com/community/ArtfulUpgrades/Kubuntu 
• https://help.ubuntu.com/community/EOLUpgrades#SpecificOlder 
• https://ubuntuforums.org/showthread.php?t=2382832 

 ---------Update----
the same steps can be followed to update from Kubunto 17.10 to 18.04
replace artful (17.10 code name) with bionic (18.04 code name) and rest of the commands, ad you're set.