diff --git a/nix/sources.json b/nix/sources.json
index c78c07f..1dd1601 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -10,5 +10,17 @@
         "type": "tarball",
         "url": "https://github.com/NixOS/nixpkgs/archive/b6eefa48d8e10491e43c0c6155ac12b463f6fed3.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-unstable": {
+        "branch": "master",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "ee9154c4c1a51a6b1129e8bf8b728ab6432eda3e",
+        "sha256": "1j1laj1b44022k2jmidp0gb8jx1yp4rsjgzcxmxkwlkv7b04bza3",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/ee9154c4c1a51a6b1129e8bf8b728ab6432eda3e.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }