Committed after system build
diff --git a/system/configuration.nix b/system/configuration.nix
index 5f1a04f..25038d5 100644
--- a/system/configuration.nix
+++ b/system/configuration.nix
@@ -278,6 +278,7 @@
 #  ];
 
   services.mongodb = {
+    package = pkgs.mongodb-5_0;
     enable = true;
     dbpath = "/tmp/mongodb";
   };