diff --git a/lib/Lacuna/RPC/Building/HallsOfVrbansk.pm b/lib/Lacuna/RPC/Building/HallsOfVrbansk.pm
index 07b39a4d..d4ec62a8 100644
--- a/lib/Lacuna/RPC/Building/HallsOfVrbansk.pm
+++ b/lib/Lacuna/RPC/Building/HallsOfVrbansk.pm
@@ -27,7 +27,7 @@ sub get_upgradable_buildings {
             y       => $building->y,
             level   => $building->level,
             image   => $building->image_level,
-            url     => $self->app_url,
+            url     => $building->controller_class->app_url,
         };
     }
     return {
diff --git a/var/www/public/changes.txt b/var/www/public/changes.txt
index fea48bad..258b861e 100644
--- a/var/www/public/changes.txt
+++ b/var/www/public/changes.txt
@@ -1,4 +1,5 @@
 2.4000
+ - Fixed bug where some spy missions would return invalid JSON.
  - Refactored ship classes.
  - Scows are no longer expendable if used to dump waste into a star.
  - Scows no longer have a 0 hold size if you have no Trade Ministry, however the Trade Ministry helps them greatly.