PHP 8.6 brings partial function application

The schedule: RC1 on September 24, more RCs on October 8, October 22 and November 5, and general availability on November 19, 2026.

The feature most people will feel is partial function application, which passed 33 to 0. Leave ? or ... in place of arguments and you get a closure back:

$f = foo(1, ?, 3);   // closure that waits for $b
$g = foo(1, ...);    // closure that waits for the rest
$out = array_map(str_replace('hello', 'hi', ?), $lines);

It pairs naturally with the pipe operator that arrived in PHP 8.5. PHP 8.6 also adds a native clamp() function.