Warning: Undefined global variable $smwgPageSpecialProperties in /var/www/html/extensions/SemanticMediaWiki/data/config/media.php on line 16

Fatal error: Uncaught TypeError: array_merge(): Argument #1 must be of type array, null given in /var/www/html/extensions/SemanticMediaWiki/data/config/media.php:16 Stack trace: #0 /var/www/html/extensions/SemanticMediaWiki/data/config/media.php(16): array_merge(NULL, Array) #1 {main} thrown in /var/www/html/extensions/SemanticMediaWiki/data/config/media.php on line 16