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.
  • parse_url now recognizes the host when a scheme is omitted, and a leading component separator is present. As of PHP 5.4.7.

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.