diff --git a/hydra/artiq.json b/hydra/artiq.json
index 092fe94..8231884 100644
--- a/hydra/artiq.json
+++ b/hydra/artiq.json
@@ -182,7 +182,7 @@
         "emailoverride": "",
         "keepnr": 50,
         "inputs": {
-            "nixpkgs": { "type": "git", "value": "https://github.com/NixOS/nixpkgs.git nixos-23.11", "emailresponsible": false },
+            "nixpkgs": { "type": "git", "value": "https://github.com/NixOS/nixpkgs.git nixos-21.05", "emailresponsible": false },
             "nixScripts": { "type": "git", "value": "https://git.m-labs.hk/M-Labs/nix-scripts.git", "emailresponsible": false },
             "urukulSrc": { "type": "git", "value": "https://github.com/quartiq/urukul.git", "emailresponsible": false },
             "mirnySrc": { "type": "git", "value": "https://github.com/quartiq/mirny.git", "emailresponsible": false },