##PHP5.3
+Added "?:" operator
+Added lambda functions and closures
+Added support for namespaces
##PHP5.4
+Added short array syntax support ([1,2,3])
+Added array dereferencing support.
+Added class member access on instantiation ( e.g. （new foo）->bar() ) support
+<?= is now always available regardless of the short_open_tag_setting
+Added binary numbers format (0b001010)
+Added support for Traits
原文：http://www.cnblogs.com/ityang666/p/php.html