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Packaging and support for O/S releases is currently addressed after those releases become Generally Available (GA). Unstable/development/testing releases can be moving targets since dependencies and behaviour may change during the O/S development cycle. Creating production-ready MongoDB packages for a new O/S release also involves standing up the testing infrastructure to run continuous integration and performance tests to try to detect unexpected behaviour or regressions. Debian 11 is currently the
testing branch for Debian – a target release date has not been announced yet but is expected later in 2021.
If you want to work with Debian 11 while it is in development, you can either compile MongoDB from source (following the
docs/build.md instructions for the specific release version you want to build on GitHub) or try to use the Debian 10 packages (which is possibly an option if the system libraries are still compatible).
If you don’t have a strict requirement to run MongoDB server processes in a local Debian 11 environment, you could also run your application code locally and connect to a remote or cloud-hosted MongoDB deployment running on a supported O/S platform.