As a long-term support release, Ubuntu 20.04 LTS (Long-Term Support) will be supported with continuous updates for a total of 5 years, meaning it will reach end-of-life around April 2025. So, in just about 3 months, Ubuntu 20.04 LTS will enter the end-of-support phase, and Canonical has started urging users to upgrade to a newer version of Ubuntu.
This means that the free version of Ubuntu 20.04 LTS will stop receiving important security updates, leaving computers running the operating system vulnerable to attack. Once this five-year period ends, any new security vulnerabilities discovered will not be patched, and bad actors may begin to target and exploit computers running this older operating system.
Ubuntu 20.04 LTS was first announced in late 2019 and officially released in April 2020. It's 2025, so five years have passed. Canonical recently issued a warning to Ubuntu 20.04 LTS users, recommending that those still running it consider upgrading to a newer version of Ubuntu. The latest LTS version is Ubuntu 24.04 LTS, and it will be supported until 2029, so you still have four years of updates for your computer and a more modern operating system. You can also upgrade directly from an older version, but there are a number of reasons why you might want to do a clean install. For example, applications and packages installed from third-party repositories (outside of the official Ubuntu "Main" and "Universe" repositories) may not be upgraded automatically and may require manual reinstallation or configuration.
The second option is to subscribe to Expanded Security Maintenance (ESM). Expanded Security Maintenance is available as an add-on to the Ubuntu Pro subscription. While large-scale businesses will have to pay, individual users who want to enable ESM can get up to five additional years of extended support by following the instructions on the Ubuntu Advantage website. Businesses also have the option to purchase the Legacy Support add-on, which extends support until April 2032.

It is important to note that the Expanded Security Maintenance program will adhere to its stated expiration date and will not be a repeat of what happened with Windows XP, where the support policy was continually extended because businesses were not ready to upgrade. For this reason, Ubuntu customers should look to upgrade to the latest version as soon as possible.
In its statement, Canonical said:
Planning for next steps is important. Running Ubuntu 20.04 without ESM means you will no longer receive security updates after April 2025. Unpatched CVE vulnerabilities could leave your system vulnerable to attack.
For those working in data-management sectors such as financial services, healthcare, or telecommunications, timely application of security patches is essential to meeting compliance standards. If you are running Ubuntu 20.04 LTS, it is time to consider your next step: upgrade to the latest Ubuntu LTS or get ESM protection through Ubuntu Pro until 2032.
Generally, the in-place upgrade process is quick and easy, but you should still make sure you have backed up important files on your system to avoid any risk of data loss. The upgrade process will also go smoother if you are using a fast, stable internet connection.