Deprecated features in PHP 5.4.x
New Functions
Migrating from PHP 5.3.x to PHP 5.4.x
PHP Manual

## Changed Functions

Several functions were given new, optional parameters in PHP 5.4:

PHP Core:

- Added the optional `limit` parameter to debug_backtrace() and debug_print_backtrace(), to limit the amount of stack frames returned.
- is_link() now works properly for symbolic links on Windows Vista or later. Earlier systems do not support symbolic links.

OpenSSL:

- Added a no padding option to the openssl_encrypt() and openssl_decrypt() functions.

Intl:

- idn_to_ascii() and idn_to_utf8() now take two extra parameters, one indicating the variant (IDNA 2003 or UTS #46) and another, passed by reference, to return details about the operation in case UTS #46 is chosen.

Deprecated features in PHP 5.4.x
New Functions
Migrating from PHP 5.3.x to PHP 5.4.x
PHP Manual