Besides zend.ze1_compatibility_mode, PHP 5 has some new configuration directives:
Extra parameters to always pass to the sendmail program, such as -oi and -t. This setting overrides the options provided as the fifth argument of mail( ). It defaults to the empty string.
Whether to register the deprecated input arrays, such as $HTTP_POST_VARS and $HTTP_GET_VARS, in addition to $_POST and $_GET. This should be enabled only for legacy code. This is set to On in php.ini-dist and to Off in php.ini-recommended.
Sets the hash function used by the session module. A value of 0 means use MD5, a 128-bit algorithm, and a value of 1 means use SHA-1, a 160-bit algorithm. It defaults to 0.
Sets the number of bits stored per character. Possible values are 4, 5, and 6; the default value is 4.