Is there any way to update Ubuntu 17.04 to 18.04 ?

Yes.

@inaba sources.list for Ubuntu 17.04 is outdated.

Iirc you'll need to go to 17.10 then to ubuntu 18.04
Google is your friend (:

Format disk, then install 18.04. That was easy.

If I'm not mostaken, on offical Ubuntu website in downloads tab you can find two options to upgrade to 18.04 LTS:
1) get full image of 18.04, flash it to usb, boot usb, choose UPGRADE option.
2) download special iso file intended for 17.04 => 18.04 upgrade, what to do next I don't really remember but hope you get the idea.

You don't, you switch to Debian /s

@Fatboy Good post. But don't tell me, tell something ud devs should be experts in using

@D--M A spying "friend"...