After installing SUPEE-7405 I will get
PHP Parse error: syntax error, unexpected '[' in /home/darmrein/public_html/app/code/core/Mage/Adminhtml/Helper/Sales.php on line 124
on my Server. So I can't open the order-single-view.
If someone has the same problem, here's the solution:
In function escapeHtmlWithLinks change
$links = ;
$links = array();
Looks like it is a problem in PHP 5.3 and earlier:
Yep, PHP 5.3 is out of action as a viable interpreter to run ecommerce websites on anyway due to security maintenance being discontinued unless you're special.
To properly address this, install the patch PHP 5.4 - Support for PHP 5.4 - Added Jan 17, 2014 if you are running Magento 1.6 or later and move on to PHP 5.4
Otherwise make the noted regression patch so Magento will function under PHP 5.3.