diff --git a/src/wp-includes/compat.php b/src/wp-includes/compat.php
index f0bdf079742f1..84e611faee5e8 100644
--- a/src/wp-includes/compat.php
+++ b/src/wp-includes/compat.php
@@ -539,6 +539,48 @@ function array_all( array $array, callable $callback ): bool { // phpcs:ignore U
 	}
 }
 
+if ( ! function_exists( 'array_first' ) ) {
+	/**
+	 * Polyfill for `array_first()` function added in PHP 8.5.
+	 *
+	 * Returns the first element of an array.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param array $array The array to get the first element from.
+	 * @return mixed|null The first element of the array, or null if the array is empty.
+	 */
+	function array_first( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
+		if ( empty( $array ) ) {
+			return null;
+		}
+
+		foreach ( $array as $value ) {
+			return $value;
+		}
+	}
+}
+
+if ( ! function_exists( 'array_last' ) ) {
+	/**
+	 * Polyfill for `array_last()` function added in PHP 8.5.
+	 *
+	 * Returns the last element of an array.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @param array $array The array to get the last element from.
+	 * @return mixed|null The last element of the array, or null if the array is empty.
+	 */
+	function array_last( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
+		if ( empty( $array ) ) {
+			return null;
+		}
+
+		return $array[ array_key_last( $array ) ];
+	}
+}
+
 // IMAGETYPE_AVIF constant is only defined in PHP 8.x or later.
 if ( ! defined( 'IMAGETYPE_AVIF' ) ) {
 	define( 'IMAGETYPE_AVIF', 19 );
diff --git a/tests/phpunit/tests/compat/arrayFirst.php b/tests/phpunit/tests/compat/arrayFirst.php
new file mode 100644
index 0000000000000..cd3708d06403b
--- /dev/null
+++ b/tests/phpunit/tests/compat/arrayFirst.php
@@ -0,0 +1,95 @@
+<?php
+
+/**
+ * @group compat
+ *
+ * @covers ::array_first
+ */
+class Tests_Compat_arrayFirst extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 63853
+	 *
+	 * Test that array_first() is always available (either from PHP or WP).
+	 */
+	public function test_array_first_availability(): void {
+		$this->assertTrue( function_exists( 'array_first' ) );
+	}
+
+	/**
+	 * @ticket 63853
+	 *
+	 * @dataProvider data_array_first
+	 *
+	 * @param mixed $expected The value extracted from the given array.
+	 * @param array $arr      The array to get the first value from.
+	 */
+	public function test_array_first( $expected, $arr ): void {
+		$this->assertSame( $expected, array_first( $arr ) );
+	}
+
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array[]
+	 */
+	public function data_array_first(): array {
+		$obj = new \stdClass();
+		return array(
+			'string values'        => array(
+				'expected' => 'a',
+				'arr'      => array( 'a', 'b', 'c' ),
+			),
+			'associative array'    => array(
+				'expected' => 10,
+				'arr'      => array(
+					'foo' => 10,
+					'bar' => 20,
+				),
+			),
+			'empty array'          => array(
+				'expected' => null,
+				'arr'      => array(),
+			),
+			'single element array' => array(
+				'expected' => 42,
+				'arr'      => array( 42 ),
+			),
+			'null values'          => array(
+				'expected' => null,
+				'arr'      => array( null, 'b', 'c' ),
+			),
+			'objects'              => array(
+				'expected' => $obj,
+				'arr'      => array(
+					$obj,
+					1,
+					2,
+				),
+			),
+			'boolean values'       => array(
+				'expected' => false,
+				'arr'      => array( false, true, 1, 2, 3 ),
+			),
+		);
+	}
+
+	/**
+	 * Test that array_first() returns the pointer is not the first element.
+	 *
+	 * @ticket 63853
+	 */
+	public function test_array_first_with_end_pointer() {
+		$arr = array(
+			'key1' => 'val1',
+			'key2' => 'val2',
+		);
+		// change the pointer to the last element
+		end( $arr );
+
+		$val = array_first( $arr );
+		$this->assertSame( 'val2', current( $arr ) );
+		$this->assertSame( 'val1', $val );
+	}
+}
diff --git a/tests/phpunit/tests/compat/arrayLast.php b/tests/phpunit/tests/compat/arrayLast.php
new file mode 100644
index 0000000000000..fc6ba394d2a02
--- /dev/null
+++ b/tests/phpunit/tests/compat/arrayLast.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * @group compat
+ *
+ * @covers ::array_last
+ */
+class Tests_Compat_arrayLast extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 63853
+	 *
+	 * Test that array_last() is always available (either from PHP or WP).
+	 */
+	public function test_array_last_availability(): void {
+		$this->assertTrue( function_exists( 'array_last' ) );
+	}
+
+	/**
+	 * @ticket 63853
+	 *
+	 * @dataProvider data_array_last
+	 *
+	 * @param mixed $expected The expected last value.
+	 * @param array $arr      The array to get the last value from.
+	 */
+	public function test_array_last( $expected, $arr ): void {
+		$this->assertSame( $expected, array_last( $arr ) );
+	}
+
+	/**
+	 * Data provider for array_last().
+	 *
+	 * @return array[]
+	 */
+	public function data_array_last(): array {
+		$obj = new \stdClass();
+		return array(
+			'string values'          => array(
+				'expected' => 'c',
+				'arr'      => array( 'a', 'b', 'c' ),
+			),
+			'associative array'      => array(
+				'expected' => 20,
+				'arr'      => array(
+					'foo' => 10,
+					'bar' => 20,
+				),
+			),
+			'empty array'            => array(
+				'expected' => null,
+				'arr'      => array(),
+			),
+			'single element array'   => array(
+				'expected' => 42,
+				'arr'      => array( 42 ),
+			),
+			'null values'            => array(
+				'expected' => null,
+				'arr'      => array( 'a', 'b', null ),
+			),
+			'objects'                => array(
+				'expected' => $obj,
+				'arr'      => array(
+					1,
+					2,
+					$obj,
+				),
+			),
+			'boolean values'         => array(
+				'expected' => false,
+				'arr'      => array( true, false ),
+			),
+			'null values in between' => array(
+				'expected' => 'c',
+				'arr'      => array( 'a', null, 'b', 'c' ),
+			),
+			'empty string values'    => array(
+				'expected' => '',
+				'arr'      => array( 'a', 'b', '' ),
+			),
+		);
+	}
+}