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
