diff --git a/core/basepage.php b/core/basepage.php
index 68b4536c..6f7e4195 100644
--- a/core/basepage.php
+++ b/core/basepage.php
@@ -731,7 +731,7 @@ class NavLink
     /**
      * @param string[] $pages_matched
      */
-    public static function is_active(array $pages_matched, string $url = null): bool
+    public static function is_active(array $pages_matched, ?string $url = null): bool
     {
         /**
          * Woo! We can actually SEE THE CURRENT PAGE!! (well... see it highlighted in the menu.)
diff --git a/core/block.php b/core/block.php
index 23fc3b58..9972cb2e 100644
--- a/core/block.php
+++ b/core/block.php
@@ -45,7 +45,7 @@ class Block
      */
     public bool $is_content = true;
 
-    public function __construct(string $header = null, string|\MicroHTML\HTMLElement $body = null, string $section = "main", int $position = 50, string $id = null)
+    public function __construct(?string $header = null, string|\MicroHTML\HTMLElement|null $body = null, string $section = "main", int $position = 50, ?string $id = null)
     {
         $this->header = $header;
         $this->body = (string)$body;
diff --git a/core/cli_app.php b/core/cli_app.php
index b6c2c5cd..a3dbdd75 100644
--- a/core/cli_app.php
+++ b/core/cli_app.php
@@ -28,7 +28,7 @@ class CliApp extends \Symfony\Component\Console\Application
         return $definition;
     }
 
-    public function run(InputInterface $input = null, OutputInterface $output = null): int
+    public function run(?InputInterface $input = null, ?OutputInterface $output = null): int
     {
         global $user;
 
diff --git a/core/config.php b/core/config.php
index 4295f28f..2f80a7f9 100644
--- a/core/config.php
+++ b/core/config.php
@@ -253,8 +253,8 @@ class DatabaseConfig extends Config
     public function __construct(
         Database $database,
         string $table_name = "config",
-        string $sub_column = null,
-        string $sub_value = null
+        ?string $sub_column = null,
+        ?string $sub_value = null
     ) {
         global $cache;
 
diff --git a/core/imageboard/misc.php b/core/imageboard/misc.php
index c4514a6c..1d1d1adb 100644
--- a/core/imageboard/misc.php
+++ b/core/imageboard/misc.php
@@ -136,7 +136,7 @@ function get_thumbnail_max_size_scaled(): array
 }
 
 
-function create_image_thumb(Image $image, string $engine = null): void
+function create_image_thumb(Image $image, ?string $engine = null): void
 {
     global $config;
     create_scaled_image(
diff --git a/core/testcase.php b/core/testcase.php
index 5e081484..6a611ce8 100644
--- a/core/testcase.php
+++ b/core/testcase.php
@@ -162,7 +162,7 @@ if (class_exists("\\PHPUnit\\Framework\\TestCase")) {
             $this->assertEquals($code, $page->code);
         }
 
-        protected function page_to_text(string $section = null): string
+        protected function page_to_text(?string $section = null): string
         {
             global $page;
             if ($page->mode == PageMode::PAGE) {
@@ -184,12 +184,12 @@ if (class_exists("\\PHPUnit\\Framework\\TestCase")) {
         /**
          * Assert that the page contains the given text somewhere in the blocks
          */
-        protected function assert_text(string $text, string $section = null): void
+        protected function assert_text(string $text, ?string $section = null): void
         {
             $this->assertStringContainsString($text, $this->page_to_text($section));
         }
 
-        protected function assert_no_text(string $text, string $section = null): void
+        protected function assert_no_text(string $text, ?string $section = null): void
         {
             $this->assertStringNotContainsString($text, $this->page_to_text($section));
         }
diff --git a/core/tests/SearchTest.php b/core/tests/SearchTest.php
index 9a346d61..5abafe1a 100644
--- a/core/tests/SearchTest.php
+++ b/core/tests/SearchTest.php
@@ -190,7 +190,7 @@ class SearchTest extends ShimmiePHPUnitTestCase
         int $limit = 9999,
         int $start = 0,
         array $res = [],
-        array $path = null,
+        ?array $path = null,
     ): void {
         global $database;
 
diff --git a/core/userclass.php b/core/userclass.php
index 1f363100..2f64fe8d 100644
--- a/core/userclass.php
+++ b/core/userclass.php
@@ -26,7 +26,7 @@ class UserClass
     /**
      * @param array<string, bool> $abilities
      */
-    public function __construct(string $name, string $parent = null, array $abilities = [])
+    public function __construct(string $name, ?string $parent = null, array $abilities = [])
     {
         $this->name = $name;
         $this->abilities = $abilities;
diff --git a/ext/bulk_actions/main.php b/ext/bulk_actions/main.php
index 7d298664..d9968c20 100644
--- a/ext/bulk_actions/main.php
+++ b/ext/bulk_actions/main.php
@@ -17,7 +17,7 @@ class BulkActionBlockBuildingEvent extends Event
     /** @var string[] */
     public array $search_terms = [];
 
-    public function add_action(string $action, string $button_text, string $access_key = null, string $confirmation_message = "", string $block = "", int $position = 40): void
+    public function add_action(string $action, string $button_text, ?string $access_key = null, string $confirmation_message = "", string $block = "", int $position = 40): void
     {
         if (!empty($access_key)) {
             assert(strlen($access_key) == 1);
diff --git a/ext/forum/theme.php b/ext/forum/theme.php
index c530cfec..08a746d9 100644
--- a/ext/forum/theme.php
+++ b/ext/forum/theme.php
@@ -34,7 +34,7 @@ class ForumTheme extends Themelet
 
 
 
-    public function display_new_thread_composer(Page $page, string $threadText = null, string $threadTitle = null): void
+    public function display_new_thread_composer(Page $page, ?string $threadText = null, ?string $threadTitle = null): void
     {
         global $config, $user;
         $max_characters = $config->get_int('forumMaxCharsPerPost');
diff --git a/ext/index/events.php b/ext/index/events.php
index 02e9ec83..121239fb 100644
--- a/ext/index/events.php
+++ b/ext/index/events.php
@@ -24,7 +24,7 @@ class SearchTermParseEvent extends Event
     /**
      * @param string[] $context
      */
-    public function __construct(int $id, string $term = null, array $context = [])
+    public function __construct(int $id, ?string $term = null, array $context = [])
     {
         parent::__construct();
 
diff --git a/ext/media/events.php b/ext/media/events.php
index a7bce3f4..abf13a10 100644
--- a/ext/media/events.php
+++ b/ext/media/events.php
@@ -27,7 +27,7 @@ class MediaResizeEvent extends Event
         int $target_width,
         int $target_height,
         string $resize_type = Media::RESIZE_TYPE_FIT,
-        string $target_mime = null,
+        ?string $target_mime = null,
         string $alpha_color = Media::DEFAULT_ALPHA_CONVERSION_COLOR,
         int $target_quality = 80,
         bool $minimize = false,
diff --git a/ext/media/main.php b/ext/media/main.php
index 0660c952..5c511446 100644
--- a/ext/media/main.php
+++ b/ext/media/main.php
@@ -548,7 +548,7 @@ class Media extends Extension
         int $new_width,
         int $new_height,
         string $output_filename,
-        string $output_mime = null,
+        ?string $output_mime = null,
         string $alpha_color = Media::DEFAULT_ALPHA_CONVERSION_COLOR,
         string $resize_type = self::RESIZE_TYPE_FIT,
         int $output_quality = 80,
diff --git a/ext/ouroboros_api/main.php b/ext/ouroboros_api/main.php
index 8fbb1659..98c7fab4 100644
--- a/ext/ouroboros_api/main.php
+++ b/ext/ouroboros_api/main.php
@@ -399,7 +399,7 @@ class OuroborosAPI extends Extension
     /**
      * Wrapper for getting a single post
      */
-    protected function postShow(int $id = null): void
+    protected function postShow(?int $id = null): void
     {
         if (!is_null($id)) {
             $post = new _SafeOuroborosImage(Image::by_id_ex($id));
diff --git a/ext/pools/main.php b/ext/pools/main.php
index 8d889449..4d5291e3 100644
--- a/ext/pools/main.php
+++ b/ext/pools/main.php
@@ -45,7 +45,7 @@ class PoolCreationEvent extends Event
 
     public function __construct(
         string $title,
-        User $pool_user = null,
+        ?User $pool_user = null,
         bool $public = false,
         string $description = ""
     ) {
diff --git a/ext/post_source/theme.php b/ext/post_source/theme.php
index a31994b6..626d3b13 100644
--- a/ext/post_source/theme.php
+++ b/ext/post_source/theme.php
@@ -36,7 +36,7 @@ class PostSourceTheme extends Themelet
         );
     }
 
-    protected function format_source(string $source = null): HTMLElement
+    protected function format_source(?string $source = null): HTMLElement
     {
         if (!empty($source)) {
             if (!str_contains($source, "://")) {
diff --git a/ext/rating/main.php b/ext/rating/main.php
index 0d4f6a40..2afc9263 100644
--- a/ext/rating/main.php
+++ b/ext/rating/main.php
@@ -440,7 +440,7 @@ class Ratings extends Extension
      * @param ImageRating[]|null $ratings
      * @return array<string, string>
      */
-    public static function get_ratings_dict(array $ratings = null): array
+    public static function get_ratings_dict(?array $ratings = null): array
     {
         if (!isset($ratings)) {
             $ratings = self::get_sorted_ratings();
diff --git a/ext/setup/main.php b/ext/setup/main.php
index 19dd2fd1..3579a5e4 100644
--- a/ext/setup/main.php
+++ b/ext/setup/main.php
@@ -181,7 +181,7 @@ class SetupBlock extends Block
         }
     }
 
-    public function add_text_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_text_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $val = html_escape($this->config->get_string($name));
 
@@ -191,7 +191,7 @@ class SetupBlock extends Block
         $this->format_option($name, $html, $label, $table_row);
     }
 
-    public function add_longtext_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_longtext_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $val = html_escape($this->config->get_string($name));
 
@@ -202,7 +202,7 @@ class SetupBlock extends Block
         $this->format_option($name, $html, $label, $table_row, true);
     }
 
-    public function add_bool_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_bool_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $checked = $this->config->get_bool($name) ? " checked" : "";
 
@@ -221,13 +221,13 @@ class SetupBlock extends Block
         $this->format_option($name, $html, null, $table_row);
     }
 
-    //	public function add_hidden_option($name, $label=null) {
+    //	public function add_hidden_option($name) {
     //		global $config;
     //		$val = $config->get_string($name);
     //		$this->body .= "<input type='hidden' id='$name' name='$name' value='$val'>";
     //	}
 
-    public function add_int_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_int_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $val = $this->config->get_int($name);
 
@@ -237,7 +237,7 @@ class SetupBlock extends Block
         $this->format_option($name, $html, $label, $table_row);
     }
 
-    public function add_shorthand_int_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_shorthand_int_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $val = to_shorthand_int($this->config->get_int($name, 0));
         $html = "<input type='text' id='$name' name='_config_$name' value='$val' size='6'>\n";
@@ -249,7 +249,7 @@ class SetupBlock extends Block
     /**
      * @param array<string,string|int> $options
      */
-    public function add_choice_option(string $name, array $options, string $label = null, bool $table_row = false): void
+    public function add_choice_option(string $name, array $options, ?string $label = null, bool $table_row = false): void
     {
         if (is_int(array_values($options)[0])) {
             $current = $this->config->get_int($name);
@@ -275,7 +275,7 @@ class SetupBlock extends Block
     /**
      * @param array<string,string> $options
      */
-    public function add_multichoice_option(string $name, array $options, string $label = null, bool $table_row = false): void
+    public function add_multichoice_option(string $name, array $options, ?string $label = null, bool $table_row = false): void
     {
         $current = $this->config->get_array($name, []);
 
@@ -294,7 +294,7 @@ class SetupBlock extends Block
         $this->format_option($name, $html, $label, $table_row);
     }
 
-    public function add_color_option(string $name, string $label = null, bool $table_row = false): void
+    public function add_color_option(string $name, ?string $label = null, bool $table_row = false): void
     {
         $val = html_escape($this->config->get_string($name));
 
diff --git a/ext/wiki/main.php b/ext/wiki/main.php
index 07a3e73d..ea67fcab 100644
--- a/ext/wiki/main.php
+++ b/ext/wiki/main.php
@@ -66,7 +66,7 @@ class WikiPage
     /**
      * @param array<string, mixed> $row
      */
-    public function __construct(array $row = null)
+    public function __construct(?array $row = null)
     {
         //assert(!empty($row));
         global $database;