Changes to INI file handling
Migrating from PHP 5.1.x to PHP 5.2.x
Migrating from PHP 5.2.x to PHP 5.3.x
PHP Manual

## Other changes

- SplFileInfo::getpathinfo() now returns information about the path name.
- SplObjectStorage now has ArrayAccess support. It is now also possible to store associative information with objects in SplObjectStorage.
- In the GD extension, there is now pixelation support available through the imagefilter() function.
- var_dump() output now includes private object members.
- session_start() now returns `FALSE` when session startup fails.
- property_exists() now checks the existence of a property independent of accessibility (like method_exists()).
- Stream wrappers can now be used by include_path.
- The `initial` parameter for array_reduce() can now be of any type.
- The directory functions opendir(), scandir(), and dir() now use the default stream context if no explicit context is passed.
- crypt() now has Blowfish and extended DES support, and crypt() features are now 100% portable. PHP has its own internal crypt implementation which drops into place when support for crypt or crypt_r is not found.
- getopt() now accepts "long options" on all platforms. Optional values and = as a separator for short options are now supported.
- fopen() has a new mode option (n), which passes `O_NONBLOCK` to the underlying open() system call. Note that this mode is not currently supported on Windows.
- getimagesize() now supports icon files (.ico).

Changes to INI file handling
Migrating from PHP 5.1.x to PHP 5.2.x
Migrating from PHP 5.2.x to PHP 5.3.x
PHP Manual