How to upgrade ubuntu from 14.04 to 18.04? [duplicate]
No.
Ubuntu does have LTS→LTS upgrades, allowing you to skip intermediate non-LTS releases...
But you can't skip intermediate LTS releases. You have to go via 16.04.
Unless you want to do a fresh install of 18.04 on release.
I should also note that the LTS upgrade pathways are usually only available some time after the main release. So don't expect to be able to upgrade from 16.04 on the day of 18.04's release.