Qubes recently announced that Qubes OS 4.0 is scheduled to reach the end of life (EOL) on August 4, 2022, which is less than a month away.
Qubes is an open source, security-focused desktop operating system, Qubes OS leverages Xen-based virtualization technology, allowing the creation and management of quartiles called qubes, providing users with better security.
The Qubes OS project uses the Semantic Versioning standard, with version numbers in the format <major>.<minor>.<patch>(major, minor, patch). When a major or minor release reaches EOL, all its patch releases will also reach EOL. So taking this situation as an example, when Qubes 4.0 reaches EOL (specified minor version, no patch number specified), Qubes 4.0.0, 4.0.1, 4.0.2, 4.0.3 and 4.0.4 will all be in Reach EOL at the same time because they both belong to the same minor patch release.
According to Qubes' support policy, after each major or minor release of Qubes OS, the previous version of Qubes OS is supported for an additional six months. This means that Qubes 4.0 will reach EOL 6 months after the release of Qubes 4.1. Since Qubes 4.1 was released in February of this year, the EOL date for Qubes 4.0 is consistent with the usual policy.
Interestingly, Qubes 4.0.0 was originally released in March 2018, which means that by the time it reached EOL, it had already had 52 months of support, which is also the longest in the project's history for a stable Qubes release support period.
If users are currently using Qubes 4.1, then this announcement has no effect on you. However, if you've been using the older Qubes 4.0, you'll need to upgrade to Qubes 4.1 before August 4th. At present, Qubes 4.1.1 has released a candidate version, and a stable version will be released in the next few weeks. Users who are not in a hurry can also wait a few weeks and upgrade to the stable version 4.1.1 directly.