16.04 LTS to 18.04.1 LTS upgrade: No new release found [duplicate]
Upgrades from 16.04 LTS will not be enabled until a few days after 18.04.1's release expected in early August. https://wiki.ubuntu.com/BionicBeaver/ReleaseSchedule
Upgrades from 16.04 LTS will not be enabled until a few days after 18.04.1's release expected in early August. https://wiki.ubuntu.com/BionicBeaver/ReleaseSchedule