Traits
This new feature allows you to reuse code in single inheritance languages like PHP. It reduces the limitation of single inheritance by giving the developers liberty to reuse a set of methods in independent classes present in different class hierarchies. Combined with classes, this new feature reduces complexity and avoids problem of multiple inheritance and Mixins.
It is to be noted that Trait is only intended for group functionality in a consistent way and is somewhat similar to a class. Also, the Trait feature cannot be instantiated on its own and it is addition to traditional inheritance for composition behavior.
Short Array syntax
Array, which is an ordered map, in PHP has been refined and can be used with list (vector), hash table, dictionaries, stack, queue and more by the developers.
Closures
PHP 5.4.0 supports Anonymous functions called closures that allow for creation of functions that don’t have any specified name. Closures can be used as the value of callback parameters and can also have many other uses.
Other than all these major additions other features like function array dereferencing, class member access on instantiation, binary number format and session extension. These new features are surely going to streamline the coding for PHP developers and bring new possibilities.