New features
  
   PHP 5.4.0 offers a wide range of new features:
  
  
   - 
    
     Support for traits has been added.
    
   
- 
    
     Short array syntax has been added, e.g. $a = [1, 2, 3, 4]; or
     $a = ['one' => 1, 'two' => 2, 'three' => 3, 'four' => 4];.
    
   
- 
    
     Function array dereferencing has been added, e.g. foo()[0].
    
   
- 
    
     Closures now support $this.
    
   
- 
    
     <?= is now always available, regardless of the
     short_open_tag php.ini option.
    
   
- 
    
     Class member access on instantiation has been added,
     e.g. (new Foo)->bar().
    
   
- 
    
     Class::{expr}() syntax is now supported.
    
   
- 
    
     Binary number format has been added, e.g. 0b001001101.
    
   
- 
    
     Improved parse error messages and improved incompatible arguments warnings.
    
   
- 
    
     The session extension can now track the upload progress of files.
    
   
- 
    
     Built-in development web server in CLI mode.