PHP 7.0.0 comes with a new version of the Zend Engine, numerous improvements
and new features such as
* Improved performance: PHP 7 is up to twice as fast as PHP 5.6
* Significantly reduced memory usage
* Abstract Syntax Tree
* Consistent 64-bit support
* Improved Exception hierarchy
* Many fatal errors converted to Exceptions
* Secure random number generator
* Removed old and unsupported SAPIs and extensions
* The null coalescing operator (??)
* Return and Scalar Type Declarations
* Anonymous Classes
* Zero cost asserts
