Qubes OS is a security-oriented Linux distribution. The main idea of the distribution is "security by isolation" using domains applied like lightweight Xen virtual machines.
Qubes OS is one operating system which gives you the Ability to create different virtual domains to perform different tasks.
So you can go from one domain to another, depending on the task you want to do, while you can also install a completely different operating system.
The latest development snapshot of the project is Qubes OS 4.2.3-rc1 which updates the operating system packages.
“We are pleased to announce the second release candidate of Qubes OS 4.2.3-rc1. Qubes OS 4.2.3-rc1 includes updates over the original version 4.2, namely:
What's new in Qubes 4.2.3?
- All security updates to date
- All bug fixes to date
More information can be found at release announcement of the project.