The Debian developers announced the change freeze for the next Debian Linux version 12 called Bookworm. The initial "freeze phase" started on January 19 2023. The second step in the freeze phase is the "soft freeze", which was announced a few days ago. This means: Debian 12 is right now in the soft freeze status.
The freeze period means no large or potentially disrupting (major changes) packages should be uploaded to Debian's "unstable" branch anymore.
Since yesterday, Debian 12 is available as Alpha 2.
As most of you probably know, each Debian release gets a nickname from a Toy Story character. The "Bookworm" character shows up in Toy Story 3 and might not be in everyone's memory.
Debian 12 contains non-free firmware!
Following a discussion between Debian Developers in 2022, Debian 12 (Bookworm) will be the first official Debian release to contain non-free firmware. This will make it easier for users with new or exotic hardware to install Debian.
How can I install and test Debian Bullseye now?
As the Debian version freeze is happening now, Bookworm is available as "Debian Testing". Currently the Alpha 2 version is available for download. Typically you'd want to download the netinst, the CD or DVD iso files.