## OOP Changelog

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
--- | ---
7.4.0 | Changed: It is now possible to throw 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-int 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 arrays.
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 provison. 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 types contexts (e.g. with `%d` modifier). As of PHP 5.2.0, converting objects 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.