php-features.txt

5.3 namespaces, closures
5.4 traits, short array syntax
5.5 finaly, generators
5.6 variadic functions, argument unpacking
7.0 return types, scalar type hints
7.1 const visibility, nullables, multiple exceptions
7.2 object type hint, abstract function override

5.3 - namespaces
    - closures
    - ?:
    - __DIR__
    - late static binding
    - __callstatic
    - goto
    - NOWDOC <<<OEF echo $a; // 3 <<<'EOF' echo $a; // $a <<<"EOF" echo $a; // 3
    - error_reporting = E_ALL // www/test; error_reporting = 0 // www/production
    - user_ini.filename = ".user.ini" - собственный аналог .htaccess
    
5.4 - traits
    - short array syntax

5.5 - finally
    - generators

5.6 - variadic functions (function foo(...$args) {}), 
    - argument unpacking (function foo($a, $b) echo foo($ar))
    - constant expressions
    - php://input is reusable
    - __debugInfo() - custom out in var_dump()
    - pgsql async support
    - `use function, use const` - in namespaces
    - 2**3 = 8 - exponention via **
    
7.0 - return types
    - scalar type hints
    - null coalescing operator (??)
    - errors to Exceptions
    - anonymous classes
    - spaceship operator (<=>)
    
7.1 - const visibility
    - nullables
    - catch multiple exceptions
    - destructurisaction (list -> [$a, $b, $c], named list)
    - iterable pseudo type hint
    
7.2 - object type hint
    - abstract function everride