diff --git a/tests/trac.nix b/tests/trac.nix
index 335d94737047..f4f91e6ccf35 100644
--- a/tests/trac.nix
+++ b/tests/trac.nix
@@ -17,6 +17,7 @@
       {
         services.openssh.enable = true;
         services.postgresql.enable = true;
+        services.postgresql.package = pkgs.postgresql92;
         services.postgresql.enableTCPIP = true;
         services.postgresql.authentication = ''
           # Generated file; do not edit!