Ubuntu 18.04.6

It is what the LTS versions have. Some have come to assure that those with a normal cycle, those supported for nine months, are only like development versions that serve to prepare everything for Long Term Support, but the truth is that those released in April of even-numbered years are supported, at least for 5 years. Bionic Beaver arrived in April 2018, and yesterday, although it was not scheduled, did your sixth point update, or what is the same, Ubuntu 18.04.6.

The fifth ISO, sixth if we count the first of all, arrived next to the eighth of Ubuntu 16.04 now more than a year ago. This it was not programmed, but Canonical has released a new ISO because key revocation has broken the installation media. The problem they wanted to solve is related to the vulnerability known as BootHole, which has caused the keys that Bionic Beaver was using to have been revoked, which is why Ubuntu 18.04.6 has been released with new keys.

Ubuntu 18.04.6 arrives fixing a security flaw and renewing keys

The Ubuntu team is pleased to announce the release of Ubuntu 18.04.6 LTS (Long-Term Support) for its desktop and server products. Unlike the previous point releases, 18.04.6 is an update to the amd64 and arm64 installation media after the key revocation related to the BootHole vulnerability, re-enabling its use on Secure Boot-enabled systems.

It should be remembered that Ubuntu 20.04 Focal Fossa was launched in April 2020, which is a newer LTS version than Bionic Beaver that has already been behind 17 months of corrections, so I think that taking the leap is already safe. If you prefer to continue using the April 2018 version or install it from scratch, it will be supported and will continue to receive updates until 2023.