diff --git a/modules/servers/postgres.nix b/modules/servers/postgres.nix
index 3b00818..72cc91d 100644
--- a/modules/servers/postgres.nix
+++ b/modules/servers/postgres.nix
@@ -5,9 +5,10 @@
   ...
 }:
 let
+  # upgrade here first, then below.
   upgrade-pg-cluster =
     let
-      newPostgres = pkgs.postgresql_16.withPackages (_pp: [ ]);
+      newPostgres = pkgs.postgresql_17.withPackages (_pp: [ ]);
     in
     pkgs.writeScriptBin "upgrade-pg-cluster" ''
       set -eux
@@ -44,7 +45,7 @@ in
     services.postgresql = {
       enable = true;
       ensureDatabases = dbNames;
-      package = pkgs.postgresql_16;
+      package = pkgs.postgresql_17;
       ensureUsers = map (name: {
         inherit name;
         ensureDBOwnership = true;