<ul><li>Fixed inc_announcements_manager.php: added $ismultisite = ($globalclass->isMultiSite()) ? 1 : 0 at entry point — was undefined when announcement_modal.php checked it at line 134</li><li>Fixed table_seen_announcements.php line 12: changed bare $filterByAnnouncement > 0 to !empty($filterByAnnouncement) && $filterByAnnouncement > 0 — variable is only set via AJAX filter, not on initial page load</li><li>Fixed category_modal.php line 21: added ?? "" null coalescing on $_REQUEST["domainid"] — key not present in URL query string</li><li>Fixed table_announcements.php and table_seen_announcements.php: added $announcements/$seenBy ?? [] guards before array_walk_recursive to prevent undefined variable warning if $announcementsmodid is falsy</li></ul>