rest_handle_deprecated_function() │ WP 4.4.0

No Hooks.

Return

null. Nothing.

Usage

rest_handle_deprecated_function( $function, $replacement, $version );
$function(string) (required)
The function that was called.
$replacement(string) (required)
The function that should have been called.
$version(string) (required)
Version.

Changelog

Since 4.4.0 Introduced.

Code of rest_handle_deprecated_function() WP 6.0

wp-includes/rest-api.php 
function rest_handle_deprecated_function( $function, $replacement, $version ) {
	if ( ! WP_DEBUG || headers_sent() ) {
		return;
	}
	if ( ! empty( $replacement ) ) {
		/* translators: 1: Function name, 2: WordPress version number, 3: New function name. */
		$string = sprintf( __( '%1$s (since %2$s; use %3$s instead)' ), $function, $version, $replacement );
	} else {
		/* translators: 1: Function name, 2: WordPress version number. */
		$string = sprintf( __( '%1$s (since %2$s; no alternative available)' ), $function, $version );
	}

	header( sprintf( 'X-WP-DeprecatedFunction: %s', $string ) );
}