New features
Changes in SAPI modules
Migrating from PHP 5.2.x to PHP 5.3.x
PHP Manual

## Changes made to Windows support

Changes to the Windows releases:

- The minimum Windows version is now Windows XP SP3; Windows 98, ME, 2000 and NT4 are no longer supported.
- Windows binaries now target i586 and later. i386 and i486 are not supported.
- There is now experimental support for x64 versions of PHP on Windows.
- There is now compiler support for Visual C++ 9 (VC9), using Visual Studio 2008. Snapshots and releases will now also be available for VC9. Old binaries using VC6 are still supported and released in the line with VC9.
- The PDO_OCI php_pdo_oci8.dll library (for use with Oracle version 8 client libraries) is no longer being built. Instead, use php_pdo_oci.dll (note no '8') with Oracle 10 or 11 client libraries. Connection to other database versions is still supported.
- For the OCI8 extension, a new library php_oci8_11g.dll is available in addition to php_oci8.dll. Only one can be enabled at any time. Use php_oci8.dll with Oracle 10.2 client libraries. Use php_oci8_11g.dll with Oracle 11 or later client libraries. Connection to other database versions is still supported.

Windows support has been added for the following functions:

- checkdnsrr()
- dns_get_record()
- fnmatch()
- getmxrr()
- getopt()
- imagecolorclosesthwb()
- inet_ntop()
- inet_pton()
- link()
- linkinfo()
- mcrypt_create_iv()
- readlink()
- socket_create_pair() - This function was previously available on Windows, but was disabled as of PHP 4.3.0 due to a bug.
- stream_socket_pair()
- symlink()
- time_nanosleep()
- time_sleep_until()

Other changes:

- Improved portability of the stat(), touch(), filemtime(), filesize() functions, and other related functions (100% portable for the available data).
- It is now possible to create hard links on Windows using the link() function, and symbolic links using the symlink() function. Hard links are available as of Windows 2000, and symbolic links as of Windows Vista.
- The Windows version of PHP now exposes a set of constants prefixed PHP_WINDOWS_*. A list of these constants and their usage can be found at Predefined Constants.

Warning

Support for the ISAPI module has been dropped. Use the improved FastCGI SAPI module instead.

> Note: A new dedicated site for PHP on Windows is now available, including downloads, release candidates, and snapshots in various flavors (thread-safe/not-thread-safe, VC6/VC9, x86/x64). The URL of this site is » http://windows.php.net/.

New features
Changes in SAPI modules
Migrating from PHP 5.2.x to PHP 5.3.x
PHP Manual