diff --git a/flake.lock b/flake.lock
index 820b5e4..c123bc4 100644
--- a/flake.lock
+++ b/flake.lock
@@ -213,6 +213,21 @@
         "type": "indirect"
       }
     },
+    "nixpkgs-23_11": {
+      "locked": {
+        "lastModified": 1701539137,
+        "narHash": "sha256-nVO/5QYpf1GwjvtpXhyxx5M3U/WN0MwBro4Lsk+9mL0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "933d7dc155096e7575d207be6fb7792bc9f34f6d",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-23.11",
+        "type": "indirect"
+      }
+    },
     "nixpkgs-stable": {
       "locked": {
         "lastModified": 1705033721,
@@ -379,19 +394,20 @@
         "nixpkgs": "nixpkgs_4",
         "nixpkgs-22_11": "nixpkgs-22_11",
         "nixpkgs-23_05": "nixpkgs-23_05",
+        "nixpkgs-23_11": "nixpkgs-23_11",
         "utils": "utils"
       },
       "locked": {
-        "lastModified": 1703666786,
-        "narHash": "sha256-SLPNpM/rI8XPyVJAxMYAe+n6NiYSpuXvdwPILHP4yZI=",
+        "lastModified": 1703023684,
+        "narHash": "sha256-XQU4OaacV0F2tf9cNAvIMqlC0HBIrAtvb0MLjIHt+7M=",
         "owner": "simple-nixos-mailserver",
         "repo": "nixos-mailserver",
-        "rev": "b5023b36a1f6628865cb42b4353bd2ddde0ea9f4",
+        "rev": "4bfb8eb058f098302c97b909df2d019926e11220",
         "type": "gitlab"
       },
       "original": {
         "owner": "simple-nixos-mailserver",
-        "ref": "master",
+        "ref": "nixos-23.11",
         "repo": "nixos-mailserver",
         "type": "gitlab"
       }