diff --git a/nix/ci.nix b/nix/ci.nix
index 1a139f3..183f8b3 100644
--- a/nix/ci.nix
+++ b/nix/ci.nix
@@ -21,6 +21,11 @@ dimension "Nixpkgs version" {
     };
     "nixos-20_03" = {
       nixpkgsSource = "nixos-20.03";
+      isReferenceNixpkgs = false;
+      enableDoc = true;
+    };
+    "nixos-20_09" = {
+      nixpkgsSource = "nixos-20.09";
       isReferenceNixpkgs = true;
       enableDoc = true;
     };
diff --git a/nix/sources.json b/nix/sources.json
index 5b1ea69..516e7c9 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -47,6 +47,18 @@
         "url": "https://github.com/NixOS/nixpkgs/archive/b4db68ff563895eea6aab4ff24fa04ef403dfe14.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
+    "nixos-20.09": {
+        "branch": "nixos-20.09",
+        "description": "Nix Packages collection",
+        "homepage": null,
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "0cfe5377e8993052f9b0dd56d058f8008af45bd9",
+        "sha256": "0i3ybddi2mrlaz3di3svdpgy93zwmdglpywih4s9rd3wj865gzn1",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/0cfe5377e8993052f9b0dd56d058f8008af45bd9.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
     "nixos-unstable": {
         "branch": "nixos-unstable",
         "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",