With Parallels Pro Control Panel for Windows 10.3.4 you can upgrade your PHP to version 5.2.8. Before updating yor PHP, make sure that you and your customers' web sites are compatible with PHP5.
The PHP version 5.2.8 is shipped with Parallels Pro Control Panel for Windows version 10.3.4. However, PHP will not be updated automatically during the product update.
To update your PHP to 5.2.8, perform the following steps before the Parallels Pro Control Panel for Windows update:
1. Download PHP 5.2.8 bundle file from the following URL: http://www.php.net/get/php-5.2.8-Win32.zip/from/a/mirror.
2. Extract the bundle to %SystemRoot%\system32\inetsrv\ for 32 bit platform or to %SystemRoot%\SysWOW64\inetsrv for x86_64 platform.
3. Rename the directory extracted from the archive to PHP (possibly you will need to rename the old PHP directory to PHP.old).
4. Delete php4ts.dll PHP4 library from %SystemRoot%\system32 folder.
5. Make sure that PHP.INI is located at the %SystemRoot%\ folder.
6. Modify the PHP.INI so that the extension_dir definition represented in the following way:
extension_dir = "C:\WINDOWS\System32\inetsrv\php\ext"
7. If you are using MySQL, make sure that the extension parameter definition represented in the following way:
8. Enable new PHP-cgi and PHP-Isapi Web service extension in the IIS settings. You can also enable All unknown CGI extension and All unknown ISAPI extension.
9. Now you can update Parallels Pro Control Panel for Windows to version 10.3.4.