CascadiaPHP 2024

Deprecated Features

PHP Core

Usage of dynamic properties

The creation of dynamic properties is deprecated, unless the class opts in by using the #[\AllowDynamicProperties] attribute. stdClass allows dynamic properties. Usage of the __get()/__set() magic methods is not affected by this change. A dynamic properties deprecation warning can be addressed by:

  • Declaring the property (preferred).
  • Adding the #[\AllowDynamicProperties] attribute to the class (which also applies to all child classes).
  • Using a WeakMap if additional data needs to be associated with an object which one does not own.

Relative callables

Callables that are not accepted by the $callable() syntax (but are accepted by call_user_func()) are deprecated. In particular:

  • "self::method"
  • "parent::method"
  • "static::method"
  • ["self", "method"]
  • ["parent", "method"]
  • ["static", "method"]
  • ["Foo", "Bar::method"]
  • [new Foo, "Bar::method"]
This does not affect normal method callables such as "A::method" or ["A", "method"].

"${var}" and "${expr}" style interpolation

The "${var}" and "${expr}" style of string interpolation is deprecated. Use "$var"/"{$var}" and "{${expr}}", respectively.


Usage of the QPrint, Base64, Uuencode, and HTML-ENTITIES 'text encodings' is deprecated for all MBString functions. Unlike all the other text encodings supported by MBString, these do not encode a sequence of Unicode codepoints, but rather a sequence of raw bytes. It is not clear what the correct return values for most MBString functions should be when one of these non-encodings is specified. Moreover, PHP has separate, built-in implementations of all of them; for example, UUencoded data can be handled using convert_uuencode()/convert_uudecode().


The internal SplFileInfo::_bad_state_ex() method has been deprecated.


utf8_encode() and utf8_decode() have been deprecated.

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