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Migrating a PHP 5.2 hosting account to PHP 5.3 or above
Different versions of PHP each have their own particular advantages and are only loosely compatible with one another; a fair percentage of scripts designed for one version will not work with a newer version and vice versa. Hence, before requesting migration to the new platform, we strongly advise you to fully test your site on your own machine (the Apache web server can be downloaded free of charge at http://www.apache.org; the different versions of PHP are available from http://www.php.org).
PHP 5.3 and later are not 100% compatible with 5.2
If you use PHP scripts which were not designed for Version 5.3, you will definitely need to check if their authors offer updates or new versions that work with Version 5.3.
The SiteBuilder tool available from your control panel is not compatible with PHP 5.3 and will no longer work.
In previous PHP versions, "register_globals" was on by default, but this is no longer the case in PHP 5.3. You will therefore need to re-enable it via an .htaccess file or else adapt your code to no longer use this method (which is actually not one of the most secure).
The Zend Optimizer module is no longer available for PHP 5.3. It has been replaced with Zend Guard Loader, which does not support files encoded for Zend Optimizer. You must therefore re-encode files specifically for Zend Guard Loader* (most CMS's using encoded files offer updates compatible with PHP 5.3/Zend Guard Loader).
Requesting PHP migration
PHP migration guide: http://us.php.net/manual/fr/migration53.php
The above guide lists incompatibilities with previous versions along with functions which are now obsolete. Using one of these functions will generate an error message. The functions are liable to be removed before too long.
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