First try to install Stalwart as a mail software

flake.lock

@@ -7,11 +7,11 @@
         "rust-overlay": "rust-overlay"
       },
       "locked": {
-        "lastModified": 1732566399,
-        "narHash": "sha256-l9bczfH/eljCxIEfuZJp6FkOy2J9vndarU1zgZFAzEY=",
+        "lastModified": 1732282930,
+        "narHash": "sha256-hC3qssnwZ9buK61th2x/C+DEQ2yUws+5zLA5Ql7Xtvs=",
         "ref": "refs/heads/main",
-        "rev": "390e71423300afd8e47a49c8d7ce39150795e8cb",
-        "revCount": 16,
+        "rev": "eef3728818c02aa6ba107825bdf45a88a544561e",
+        "revCount": 12,
         "type": "git",
         "url": "https://gitea.mathebau.de/fachschaft/alias_to_sieve"
       },
@@ -231,11 +231,11 @@
         "nixpkgs": "nixpkgs_2"
       },
       "locked": {
-        "lastModified": 1732328983,
-        "narHash": "sha256-RHt12f/slrzDpSL7SSkydh8wUE4Nr4r23HlpWywed9E=",
+        "lastModified": 1732242723,
+        "narHash": "sha256-NWI8csIK0ujFlFuEXKnoc+7hWoCiEtINK9r48LUUMeU=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "ed8aa5b64f7d36d9338eb1d0a3bb60cf52069a72",
+        "rev": "a229311fcb45b88a95fdfa5cecd8349c809a272a",
         "type": "github"
       },
       "original": {