Deprecated Features

PHP Core

  • If a parameter with a default value is followed by a required parameter, the default value has no effect. This is deprecated as of PHP 8.0.0 and can generally be resolved by dropping the default value, without a change in functionality:

    function test($a = [], $b) {} // Before
    function test($a$b) {}      // After

    One exception to this rule are parameters of the form Type $param = null, where the null default makes the type implicitly nullable. This usage remains allowed, but it is recommended to use an explicit nullable type instead:

    function test(A $a null$b) {} // Still allowed
    function test(?A $a$b) {}       // Recommended

  • Calling get_defined_functions() with exclude_disabled explicitly set to false is deprecated and no longer has an effect. get_defined_functions() will never include disabled functions.



libxml_disable_entity_loader() has been deprecated. As libxml 2.9.0 is now required, external entity loading is guaranteed to be disabled by default, and this function is no longer needed to protect against XXE attacks, unless the (still vulnerable). LIBXML_NOENT is used. In that case, it is recommended to refactor the code using libxml_set_external_entity_loader() to suppress loading of external entities.


Standard Library

  • Sort comparison functions that return true or false will now throw a deprecation warning, and should be replaced with an implementation that returns an integer less than, equal to, or greater than zero.

    // Replace
    usort($arrayfn($a$b) => $a $b);
    // With
    usort($arrayfn($a$b) => $a <=> $b);


  • Using an empty file as ZipArchive is deprecated. Libzip 1.6.0 does not accept empty files as valid zip archives any longer. The existing workaround will be removed in the next version.

  • The procedural API of Zip is deprecated. Use ZipArchive instead. Iteration over all entries can be accomplished using ZipArchive::statIndex() and a for loop:

    // iterate using the procedural API
    while (
    $entry zip_read($zip)) {

    // iterate using the object-oriented API
    assert($zip instanceof ZipArchive);
    for (
    $i 0$entry $zip->statIndex($i); $i++) {


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