Changes to the PHP OOP model are logged here. Descriptions and other notes regarding these features are documented within the OOP model documentation. &Version; &Description; 8.4.0 Added: Support for Property Hooks. 8.4.0 Added: Support for Lazy Objects. 8.1.0 Added: Support for the final modifier for class constants. Also, interface constants become overridable by default. 8.0.0 Added: Support for the nullsafe operator ?-> to access properties and methods on objects that may be null. 7.4.0 Changed: It is now possible to throw an exception within __toString. 7.4.0 Added: Support for limited return type covariance and argument type contravariance. Full variance support is only available if autoloading is used. Inside a single file only non-cyclic type references are possible. 7.4.0 Added: It is now possible to type class properties. 7.3.0 Incompatibility: Argument unpacking of Traversables with non-&integer; keys is no longer supported. This behaviour was not intended and thus has been removed. 7.3.0 Incompatibility: In previous versions it was possible to separate the static properties by assigning a reference. This has been removed. 7.3.0 Changed: The instanceof operator now allows literals as the first operand, in which case the result is always &false;. 7.2.0 Deprecated: The __autoload method has been deprecated in favour of spl_autoload_register. 7.2.0 Changed: The following name cannot be used to name classes, interfaces, or traits: object. 7.2.0 Changed: A trailing comma can now be added to the group-use syntax for namespaces. 7.2.0 Changed: Parameter type widening. Parameter types from overridden methods and from interface implementations may now be omitted. 7.2.0 Changed: Abstract methods can now be overridden when an abstract class extends another abstract class. 7.1.0 Changed: The following names cannot be used to name classes, interfaces, or traits: void and iterable. 7.1.0 Added: It is now possible to specify the visibility of class constants. 7.0.0 Deprecated: Static calls to methods that are not declared static. 7.0.0 Deprecated: PHP 4 style constructor. I.e. methods that have the same name as the class they are defined in. 7.0.0 Added: Group use declaration: classes, functions and constants being imported from the same namespace can now be grouped together in a single use statement. 7.0.0 Added: Support for anonymous classes has been added via new class. 7.0.0 Incompatibility: Iterating over a non-Traversable &object; will now have the same behaviour as iterating over by-reference &array;s. 7.0.0 Changed: Defining (compatible) properties in two used traits no longer triggers an error. 5.6.0 Added: The __debugInfo() method. 5.5.0 Added: The ::class magic constant. 5.5.0 Added: finally to handle exceptions. 5.4.0 Added: traits. 5.4.0 Changed: If an abstract class defines a signature for the constructor it will now be enforced. 5.3.3 Changed: Methods with the same name as the last element of a namespaced class name will no longer be treated as constructor. This change doesn't affect non-namespaced classes. 5.3.0 Changed: Classes that implement interfaces with methods that have default values in the prototype are no longer required to match the interface's default value. 5.3.0 Changed: It's now possible to reference the class using a variable (e.g., echo $classname::constant;). The variable's value can not be a keyword (e.g., self, parent or static). 5.3.0 Changed: An E_WARNING level error is issued if the magic overloading methods are declared static. It also enforces the public visibility requirement. 5.3.0 Changed: Prior to 5.3.0, exceptions thrown in the __autoload function could not be caught in the catch block, and would result in a fatal error. Exceptions now thrown in the __autoload function can be caught in the catch block, with one provision. If throwing a custom exception, then the custom exception class must be available. The __autoload function may be used recursively to autoload the custom exception class. 5.3.0 Added: The __callStatic method. 5.3.0 Added: heredoc and nowdoc support for class const and property definitions. Note: heredoc values must follow the same rules as double-quoted strings, (e.g. no variables within). 5.3.0 Added: Late Static Bindings. 5.3.0 Added: The __invoke() method. 5.2.0 Changed: The __toString() method was only called when it was directly combined with echo or print. But now, it is called in any &string; context (e.g. in printf with %s modifier) but not in other type contexts (e.g. with %d modifier). As of PHP 5.2.0, converting &object;s without a __toString method to &string; emits a E_RECOVERABLE_ERROR level error. 5.1.3 Changed: In previous versions of PHP 5, the use of var was considered deprecated and would issue an E_STRICT level error. It's no longer deprecated, therefore does not emit the error. 5.1.0 Changed: The __set_state() static method is now called for classes exported by var_export. 5.1.0 Added: The __isset() and __unset() methods.