diff --git a/phpBB/includes/acp/acp_styles.php b/phpBB/includes/acp/acp_styles.php
index b04ed3d652..a500a6b721 100644
--- a/phpBB/includes/acp/acp_styles.php
+++ b/phpBB/includes/acp/acp_styles.php
@@ -1203,7 +1203,7 @@ class acp_styles
 		}
 
 		$json = file_get_contents($this->styles_path . $dir . '/composer.json');
-		$style_data = \phpbb\json_sanitizer::decode($json);
+		$style_data = \phpbb\json\sanitizer::decode($json);
 
 		if (!is_array($style_data) || !isset($style_data['type']) || $style_data['type'] !== 'phpbb-style')
 		{
diff --git a/phpBB/phpbb/cache/service.php b/phpBB/phpbb/cache/service.php
index 950080ef48..acf343e194 100644
--- a/phpBB/phpbb/cache/service.php
+++ b/phpBB/phpbb/cache/service.php
@@ -13,7 +13,7 @@
 
 namespace phpbb\cache;
 
-use phpbb\json_sanitizer;
+use phpbb\json\sanitizer;
 
 /**
 * Class for grabbing/handling cached entries
@@ -357,7 +357,7 @@ class service
 		{
 			// Re-parse cfg file
 			$json = file_get_contents($filename);
-			$parsed_array = json_sanitizer::decode($json);
+			$parsed_array = sanitizer::decode($json);
 			$parsed_array['filetime'] = @filemtime($filename);
 
 			$this->driver->put('_cfg_' . $style['style_path'], $parsed_array);
diff --git a/phpBB/phpbb/db/migration/data/v310/style_update_p1.php b/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
index 0ba9b86a33..a6f1c1fa13 100644
--- a/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
+++ b/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
@@ -13,7 +13,7 @@
 
 namespace phpbb\db\migration\data\v310;
 
-use phpbb\json_sanitizer;
+use phpbb\json\sanitizer;
 
 class style_update_p1 extends \phpbb\db\migration\migration
 {
@@ -85,7 +85,7 @@ class style_update_p1 extends \phpbb\db\migration\migration
 				else if (file_exists($fileinfo->getPathname() . '/composer.json'))
 				{
 					$json = file_get_contents($fileinfo->getPathname() . '/composer.json');
-					$style_data = json_sanitizer::decode($json);
+					$style_data = sanitizer::decode($json);
 					if (isset($style_data['extra']['phpbb-version']) && version_compare($style_data['extra']['phpbb-version'], '3.3.0-dev', '>='))
 					{
 						// 3.3 style
diff --git a/phpBB/phpbb/json/sanitizer.php b/phpBB/phpbb/json/sanitizer.php
index 8d6937e630..ea3112ee37 100644
--- a/phpBB/phpbb/json/sanitizer.php
+++ b/phpBB/phpbb/json/sanitizer.php
@@ -1,24 +1,25 @@
 <?php
+declare(strict_types=1);
 /**
-*
-* This file is part of the phpBB Forum Software package.
-*
-* @copyright (c) phpBB Limited <https://www.phpbb.com>
-* @license GNU General Public License, version 2 (GPL-2.0)
-*
-* For full copyright and license information, please see
-* the docs/CREDITS.txt file.
-*
-*/
+ *
+ * This file is part of the phpBB Forum Software package.
+ *
+ * @copyright (c) phpBB Limited <https://www.phpbb.com>
+ * @license GNU General Public License, version 2 (GPL-2.0)
+ *
+ * For full copyright and license information, please see
+ * the docs/CREDITS.txt file.
+ *
+ */
 
-namespace phpbb;
+namespace phpbb\json;
 
 use phpbb\request\type_cast_helper;
 
 /**
-* JSON sanitizer class
-*/
-class json_sanitizer
+ * JSON sanitizer class
+ */
+class sanitizer
 {
 	/**
 	 * Sanitize json data
@@ -27,7 +28,7 @@ class json_sanitizer
 	 *
 	 * @return array Sanitized data
 	 */
-	static public function sanitize($data)
+	static public function sanitize(array $data) : array
 	{
 		if (!empty($data))
 		{
@@ -48,7 +49,7 @@ class json_sanitizer
 	 *
 	 * @return array Data array
 	 */
-	static public function decode($json)
+	static public function decode(string $json) : array
 	{
 		$data = json_decode($json, true);
 		return !empty($data) ? self::sanitize($data) : [];
diff --git a/phpBB/phpbb/language/language_file_helper.php b/phpBB/phpbb/language/language_file_helper.php
index de395b64bd..d5fc716e1c 100644
--- a/phpBB/phpbb/language/language_file_helper.php
+++ b/phpBB/phpbb/language/language_file_helper.php
@@ -13,7 +13,7 @@
 
 namespace phpbb\language;
 
-use phpbb\json_sanitizer;
+use phpbb\json\sanitizer;
 use Symfony\Component\Finder\Finder;
 
 /**
@@ -55,7 +55,7 @@ class language_file_helper
 		foreach ($finder as $file)
 		{
 			$json = $file->getContents();
-			$data = json_sanitizer::decode($json);
+			$data = sanitizer::decode($json);
 
 			$available_languages[] = $this->get_language_data_from_json($data);
 		}
@@ -72,7 +72,7 @@ class language_file_helper
 	public function get_language_data_from_composer_file($path)
 	{
 		$json_data = file_get_contents($path);
-		return $this->get_language_data_from_json(json_sanitizer::decode($json_data));
+		return $this->get_language_data_from_json(sanitizer::decode($json_data));
 	}
 
 	/**
diff --git a/phpBB/phpbb/version_helper.php b/phpBB/phpbb/version_helper.php
index 5bcd311ffe..7c6edbea95 100644
--- a/phpBB/phpbb/version_helper.php
+++ b/phpBB/phpbb/version_helper.php
@@ -390,7 +390,7 @@ class version_helper
 			}
 
 			// Sanitize any data we retrieve from a server
-			$info = json_sanitizer::decode($info);
+			$info = json\sanitizer::decode($info);
 
 			if (empty($info['stable']) && empty($info['unstable']))
 			{