diff --git a/doc/preface.chapter.md b/doc/preface.chapter.md
index e6a0905c5a95..56f089703021 100644
--- a/doc/preface.chapter.md
+++ b/doc/preface.chapter.md
@@ -42,7 +42,7 @@ shows the status of tests for the `nixpkgs-unstable` channel.
 
 The tests are conducted by a cluster called [Hydra](https://nixos.org/hydra/),
 which also builds binary packages from the Nix expressions in Nixpkgs for
-`x86_64-linux`, `i686-linux` and `x86_64-darwin`.
+`x86_64-linux`, `aarch64-linux`, `x86_64-darwin` and `aarch64-darwin`.
 The binaries are made available via a [binary cache](https://cache.nixos.org).
 
 The current Nix expressions of the channels are available in the