NixOS 19.09 beta release

I’m excited to announce the NixOS 19.09 beta release branch has been created!

Some relevant links:

Hydra jobset: Hydra - Jobset nixos:release-19.09
ZHF Issue: Zero Hydra Failures: 19.09 edition · Issue #68361 · NixOS/nixpkgs · GitHub

We look forward to everyone helping make this release as stable as possible. Start your testing engines!