diff --git a/nixos/boxes/brix/matrix-server.nix b/nixos/boxes/brix/matrix-server.nix
index 1030a2c6..f0fc6dd2 100644
--- a/nixos/boxes/brix/matrix-server.nix
+++ b/nixos/boxes/brix/matrix-server.nix
@@ -35,7 +35,7 @@
     extraConfig = ''
       experimental_features: { spaces_enabled: true }
     '';
-    package = inputs.nixpkgs.legacyPackages."x86_64-linux".matrix-synapse;
+    package = inputs.nixpkgs-nixos-unstable.legacyPackages."x86_64-linux".matrix-synapse;
   };
 
   networking.firewall.allowedTCPPorts = [ 8008 ];