vbullietin 4.20

[66Anonymous69]

hello i,m a noob about scripting i could need some advice
i try to install the script but it wand let me because a Error
Fatal error: Array and string offset access syntax with curly braces is no longer supported in /data/sites/web/ my site name /www/includes/functions.php on line 869
When i open functions.php on line 869 it let me see this

$newpassword .= $password_characters{vbrand(0, $total_password_characters)};
}

so i don't know what wrong white it
Sorry for my bad English and explaining