PHP 5.4
    
    CLASSES/INTERFACES
    ==================
    CallbackFilterIterator
    RecursiveCallbackFilterIterator
    
    SessionHandler
    Transliterator
    Spoofchecker

PHP 5.5

    FUNCTIONS
    =========
    curl_escape()
    curl_unescape()
    pg_escape_literal()
    pg_escape_identifier()
    
    CLASSES/INTERFACES
    ==================
    DateTimeImmutable
    DateTimeInterface
    IntlCalendar
    IntlGregorianCalendar
    IntlTimeZone
    IntlBreakIterator
    IntlRuleBasedBreakIterator
    IntlCodePointBreakIterator 

PHP 5.6

    gmp_root()
    gmp_rootrem()
    ldap_escape()
    ldap_modify_batch()