Qubes OS, a security-oriented Linux distro targeting desktop users and built around containerization that, instead of relying on a single, monolithic system, isolates applications and workloads into separate virtual machines called qubes, has just released Qubes OS 4.3.
At the core of the system, dom0, the privileged administrative virtual machine that controls the system, has been upgraded to Fedora 41, bringing newer tooling and improved long-term maintainability for the trusted administrative domain. The underlying hypervisor has also been updated to Xen 4.19.
Template updates are one of the most significant changes in this release. The default Fedora template has been updated to Fedora 42, while the default Debian template has been upgraded to Debian 13. The bundled Whonix templates have also been updated to Whonix 18. Older template versions are no longer supported.
Qubes OS 4.3 also introduces preloaded disposable qubes, reducing setup friction for users who rely on short-lived, isolated environments for tasks such as opening untrusted files or browsing risky content. Device handling has been modernized with a new self-identity-oriented device assignment model, commonly known as the New Devices API, improving clarity and control when assigning hardware to specific qubes.
Another notable addition is the return of Qubes Windows Tools, which have been reintroduced with improved features and better integration. This restores functionality that many users depend on when running Windows virtual machines alongside Linux-based qubes.
For new installations, Qubes OS 4.3 is available as a fresh ISO image. Users upgrading from Qubes OS 4.2 can follow the documented in-place upgrade path, while those running a 4.3 release candidate only need to update normally to reach parity with the stable release. In all scenarios, the project strongly recommends performing a full backup before proceeding.
The release includes a known issue affecting templates restored from backups created before Qubes OS 4.3. In such cases, restored templates may still point to older repositories and require a manual distribution upgrade step. Clean installations and in-place upgrades from 4.2 are not affected.
For more information, see the announcement.
