diff --git a/functionMap.php b/functionMap.php
index 7f2c32f..384a6fa 100644
--- a/functionMap.php
+++ b/functionMap.php
@@ -42,9 +42,11 @@
     'stripslashes_deep' => ['T', '@phpstan-template' => 'T', 'value' => 'T'],
     'urldecode_deep' => ['T', '@phpstan-template' => 'T', 'value' => 'T'],
     'urlencode_deep' => ['T', '@phpstan-template' => 'T', 'value' => 'T'],
+    'wp_dropdown_languages' => ["(\$args is array{id: null|''} ? void : (\$args is array{name: null|''} ? void : string))"],
     'wp_clear_scheduled_hook' => ['(0|positive-int|($wp_error is false ? false : \WP_Error))', 'args' => $cronArgsType],
     'wp_get_schedule' => [null, 'args' => $cronArgsType],
     'wp_get_scheduled_event' => [null, 'args' => $cronArgsType],
+    'wp_get_archives' => ['($args is array{echo: false|0} ? string : void)'],
     'WP_Http::get' => [$httpReturnType],
     'WP_Http::head' => [$httpReturnType],
     'WP_Http::post' => [$httpReturnType],
diff --git a/tests/TypeInferenceTest.php b/tests/TypeInferenceTest.php
index 8e413c3..68c9e2f 100644
--- a/tests/TypeInferenceTest.php
+++ b/tests/TypeInferenceTest.php
@@ -32,7 +32,9 @@ public function dataFileAsserts(): iterable
         yield from $this->gatherAssertTypes(__DIR__ . '/data/mysql2date.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/term_exists.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_debug_backtrace_summary.php');
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_dropdown_languages.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_error_parameter.php');
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_get_archives.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_list_pages.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_rest_request.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/wp_theme.php');
diff --git a/tests/data/wp_dropdown_languages.php b/tests/data/wp_dropdown_languages.php
new file mode 100644
index 0000000..38d452b
--- /dev/null
+++ b/tests/data/wp_dropdown_languages.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * Note:
+ * Starting from PHPStan 1.10.49, void types, including void in unions, are
+ * transformed into null.
+ *
+ * @link https://github.com/phpstan/phpstan-src/pull/2778
+ */
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use function wp_dropdown_languages;
+use function PHPStan\Testing\assertType;
+
+/** @var ''|null $emptyStringOrNull */
+$emptyStringOrNull = $_GET['nullOrEmptyString'];
+
+/** @var string|null $stringOrNull */
+$stringOrNull = $_GET['unknown'];
+
+// Default value
+assertType('string', wp_dropdown_languages());
+assertType('string', wp_dropdown_languages(['selected' => '']));
+
+// Void return type
+assertType('null', wp_dropdown_languages(['id' => $emptyStringOrNull, 'selected' => '']));
+assertType('null', wp_dropdown_languages(['name' => $emptyStringOrNull, 'selected' => '']));
+assertType('null', wp_dropdown_languages(['id' => $emptyStringOrNull, 'name' => $emptyStringOrNull, 'selected' => '']));
+
+// string return type
+assertType('string', wp_dropdown_languages(['id' => 'nonEmptyString', 'selected' => '']));
+assertType('string', wp_dropdown_languages(['name' => 'nonEmptyString', 'selected' => '']));
+assertType('string', wp_dropdown_languages(['id' => 'nonEmptyString', 'name' => 'nonEmptyString', 'selected' => '']));
+
+// Unknown value
+assertType('string|null', wp_dropdown_languages(['id' => $stringOrNull, 'selected' => '']));
+assertType('string|null', wp_dropdown_languages(['name' => $stringOrNull, 'selected' => '']));
+assertType('string|null', wp_dropdown_languages(['id' => $stringOrNull, 'name' => $stringOrNull, 'selected' => '']));
+assertType('string|null', wp_dropdown_languages(['id' => 'nonEmptyString', 'name' => $stringOrNull, 'selected' => '']));
+assertType('string|null', wp_dropdown_languages(['id' => $stringOrNull, 'name' => 'nonEmptyString', 'selected' => '']));
diff --git a/tests/data/wp_get_archives.php b/tests/data/wp_get_archives.php
new file mode 100644
index 0000000..544996d
--- /dev/null
+++ b/tests/data/wp_get_archives.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * Note:
+ * Starting from PHPStan 1.10.49, void types, including void in unions, are
+ * transformed into null.
+ *
+ * @link https://github.com/phpstan/phpstan-src/pull/2778
+ */
+
+declare(strict_types=1);
+
+namespace PhpStubs\WordPress\Core\Tests;
+
+use function wp_get_archives;
+use function PHPStan\Testing\assertType;
+
+// Default value of true
+assertType('null', wp_get_archives());
+
+// Explicit value of true|1
+assertType('null', wp_get_archives(['echo' => true, 'key' => 'value']));
+assertType('null', wp_get_archives(['echo' => 1, 'key' => 'value']));
+
+// Explicit value of false|0
+assertType('string', wp_get_archives(['echo' => false, 'key' => 'value']));
+assertType('string', wp_get_archives(['echo' => 0, 'key' => 'value']));
+
+// Unknown value
+assertType('string|null', wp_get_archives(['echo' => (bool)$GET['echo'], 'key' => 'value']));
+assertType('string|null', wp_get_archives(['echo' => (int)$GET['echo'], 'key' => 'value']));
diff --git a/wordpress-stubs.php b/wordpress-stubs.php
index 949fe13..ae00d8d 100644
--- a/wordpress-stubs.php
+++ b/wordpress-stubs.php
@@ -117188,6 +117188,7 @@ function get_archives_link($url, $text, $format = 'html', $before = '', $after =
      *   day?: string,
      *   w?: string,
      * } $args
+     * @phpstan-return ($args is array{echo: false|0} ? string : void)
      */
     function wp_get_archives($args = '')
     {
@@ -120776,6 +120777,7 @@ function wp_get_l10n_php_file_data($php_file)
      *   show_option_en_us?: bool,
      *   explicit_option_en_us?: bool,
      * } $args
+     * @phpstan-return ($args is array{id: null|''} ? void : ($args is array{name: null|''} ? void : string))
      */
     function wp_dropdown_languages($args = array())
     {