What is the PHP's short_open_tag
PHP's short_open_tag is a way to use PHP in a PHP script without the normal PHP tag, e.g.
# <?php echo "hello world"; ?>
You can use a simplified version.
# <? echo "hello world"; ?>
Although it is not recommended, if you want to set it, you can enable it by editing the php.ini
Locate and set
short_open_tag = On
Also, remember to restart web server such as Apache if needed.