diff --git a/phpBB/includes/acp/acp_search.php b/phpBB/includes/acp/acp_search.php
index a2f3b97186..53fc6f5925 100644
--- a/phpBB/includes/acp/acp_search.php
+++ b/phpBB/includes/acp/acp_search.php
@@ -79,29 +79,29 @@ class acp_search
 
 		foreach ($search_types as $search)
 		{
-			$type = get_class($search);
+			// Only show available search backends
+			if($search->is_available()) {
 
-			$name = $search->get_name();
+				$name = $search->get_name();
 
-			$selected = ($config['search_type'] == $type) ? ' selected="selected"' : '';
-			$identifier = substr($type, strrpos($type, '\\') + 1);
-			$search_options .= "<option value=\"$type\"$selected data-toggle-setting=\"#search_{$identifier}_settings\">$name</option>";
+				$type = get_class($search);
 
-			if (method_exists($search, 'acp'))
-			{
-				$vars = $search->acp();
+				$selected = ($config['search_type'] == $type) ? ' selected="selected"' : '';
+				$identifier = substr($type, strrpos($type, '\\') + 1);
+				$search_options .= "<option value=\"$type\"$selected data-toggle-setting=\"#search_{$identifier}_settings\">$name</option>";
 
-				if (!$submit)
-				{
-					$template->assign_block_vars('backend', array(
-						'NAME'			=> $name,
-						'SETTINGS'		=> $vars['tpl'],
-						'IDENTIFIER'	=> $identifier,
-					));
-				}
-				else if (is_array($vars['config']))
-				{
-					$settings = array_merge($settings, $vars['config']);
+				if (method_exists($search, 'acp')) {
+					$vars = $search->acp();
+
+					if (!$submit) {
+						$template->assign_block_vars('backend', array(
+							'NAME' => $name,
+							'SETTINGS' => $vars['tpl'],
+							'IDENTIFIER' => $identifier,
+						));
+					} else if (is_array($vars['config'])) {
+						$settings = array_merge($settings, $vars['config']);
+					}
 				}
 			}
 		}
diff --git a/phpBB/phpbb/search/backend/fulltext_mysql.php b/phpBB/phpbb/search/backend/fulltext_mysql.php
index 116ab67201..e95596022b 100644
--- a/phpBB/phpbb/search/backend/fulltext_mysql.php
+++ b/phpBB/phpbb/search/backend/fulltext_mysql.php
@@ -116,6 +116,14 @@ class fulltext_mysql extends base implements search_backend_interface
 		return 'MySQL Fulltext';
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_available(): bool
+	{
+		return $this->db->get_sql_layer() == 'mysqli';
+	}
+
 	/**
 	 * {@inheritdoc}
 	 */
@@ -147,7 +155,7 @@ class fulltext_mysql extends base implements search_backend_interface
 	*/
 	public function init()
 	{
-		if ($this->db->get_sql_layer() != 'mysqli')
+		if (!$this->is_available())
 		{
 			return $this->user->lang['FULLTEXT_MYSQL_INCOMPATIBLE_DATABASE'];
 		}
diff --git a/phpBB/phpbb/search/backend/fulltext_native.php b/phpBB/phpbb/search/backend/fulltext_native.php
index b7105f8cd6..81541930a7 100644
--- a/phpBB/phpbb/search/backend/fulltext_native.php
+++ b/phpBB/phpbb/search/backend/fulltext_native.php
@@ -23,12 +23,12 @@ use phpbb\user;
 */
 class fulltext_native extends base implements search_backend_interface
 {
-	const UTF8_HANGUL_FIRST = "\xEA\xB0\x80";
-	const UTF8_HANGUL_LAST = "\xED\x9E\xA3";
-	const UTF8_CJK_FIRST = "\xE4\xB8\x80";
-	const UTF8_CJK_LAST = "\xE9\xBE\xBB";
-	const UTF8_CJK_B_FIRST = "\xF0\xA0\x80\x80";
-	const UTF8_CJK_B_LAST = "\xF0\xAA\x9B\x96";
+	protected const UTF8_HANGUL_FIRST = "\xEA\xB0\x80";
+	protected const UTF8_HANGUL_LAST = "\xED\x9E\xA3";
+	protected const UTF8_CJK_FIRST = "\xE4\xB8\x80";
+	protected const UTF8_CJK_LAST = "\xE9\xBE\xBB";
+	protected const UTF8_CJK_B_FIRST = "\xF0\xA0\x80\x80";
+	protected const UTF8_CJK_B_LAST = "\xF0\xAA\x9B\x96";
 
 	/**
 	 * Associative array holding index stats
@@ -149,6 +149,14 @@ class fulltext_native extends base implements search_backend_interface
 		return 'phpBB Native Fulltext';
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_available(): bool
+	{
+		return true;
+	}
+
 	/**
 	 * {@inheritdoc}
 	 */
diff --git a/phpBB/phpbb/search/backend/fulltext_postgres.php b/phpBB/phpbb/search/backend/fulltext_postgres.php
index 41b28bff61..234b820f29 100644
--- a/phpBB/phpbb/search/backend/fulltext_postgres.php
+++ b/phpBB/phpbb/search/backend/fulltext_postgres.php
@@ -56,7 +56,7 @@ class fulltext_postgres extends base implements search_backend_interface
 
 	/**
 	 * Database connection
-	 * @var \phpbb\db\driver\driver_interface
+	 * @var driver_interface
 	 */
 	protected $db;
 
@@ -129,6 +129,14 @@ class fulltext_postgres extends base implements search_backend_interface
 		return 'PostgreSQL Fulltext';
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_available(): bool
+	{
+		return $this->db->get_sql_layer() == 'postgres';
+	}
+
 	/**
 	 * {@inheritdoc}
 	 */
@@ -170,7 +178,7 @@ class fulltext_postgres extends base implements search_backend_interface
 	*/
 	public function init()
 	{
-		if ($this->db->get_sql_layer() != 'postgres')
+		if (!$this->is_available())
 		{
 			return $this->user->lang['FULLTEXT_POSTGRES_INCOMPATIBLE_DATABASE'];
 		}
@@ -1047,7 +1055,7 @@ class fulltext_postgres extends base implements search_backend_interface
 	}
 
 	/**
-	 * Computes the stats and store them in the $this->stats associative array
+	 * {@inheritdoc}
 	 */
 	protected function get_stats()
 	{
diff --git a/phpBB/phpbb/search/backend/fulltext_sphinx.php b/phpBB/phpbb/search/backend/fulltext_sphinx.php
index da8c949b56..c53116af71 100644
--- a/phpBB/phpbb/search/backend/fulltext_sphinx.php
+++ b/phpBB/phpbb/search/backend/fulltext_sphinx.php
@@ -16,6 +16,7 @@ namespace phpbb\search\backend;
 use phpbb\auth\auth;
 use phpbb\config\config;
 use phpbb\db\driver\driver_interface;
+use phpbb\db\tools\tools_interface;
 use phpbb\event\dispatcher_interface;
 use phpbb\user;
 
@@ -85,13 +86,13 @@ class fulltext_sphinx implements search_backend_interface
 
 	/**
 	 * Database connection
-	 * @var \phpbb\db\driver\driver_interface
+	 * @var driver_interface
 	 */
 	protected $db;
 
 	/**
 	 * Database Tools object
-	 * @var \phpbb\db\tools\tools_interface
+	 * @var tools_interface
 	 */
 	protected $db_tools;
 
@@ -180,6 +181,14 @@ class fulltext_sphinx implements search_backend_interface
 		return 'Sphinx Fulltext';
 	}
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function is_available(): bool
+	{
+		return ($this->db->get_sql_layer() == 'mysqli' || $this->db->get_sql_layer() == 'postgres') && class_exists('SphinxClient');
+	}
+
 	/**
 	 * {@inheritdoc}
 	 */
@@ -211,7 +220,7 @@ class fulltext_sphinx implements search_backend_interface
 	*/
 	public function init()
 	{
-		if ($this->db->get_sql_layer() != 'mysqli' && $this->db->get_sql_layer() != 'postgres')
+		if (!$this->is_available())
 		{
 			return $this->user->lang['FULLTEXT_SPHINX_WRONG_DATABASE'];
 		}
@@ -922,9 +931,7 @@ class fulltext_sphinx implements search_backend_interface
 	}
 
 	/**
-	* Returns an associative array containing information about the indexes
-	*
-	* @return string|bool Language string of error false otherwise
+	 * {@inheritdoc}
 	*/
 	public function index_stats()
 	{
diff --git a/phpBB/phpbb/search/backend/search_backend_interface.php b/phpBB/phpbb/search/backend/search_backend_interface.php
index 7c7b60cb12..26c87909b9 100644
--- a/phpBB/phpbb/search/backend/search_backend_interface.php
+++ b/phpBB/phpbb/search/backend/search_backend_interface.php
@@ -22,6 +22,13 @@ interface search_backend_interface
 	*/
 	public function get_name();
 
+	/**
+	 * Returns if the search engine is available
+	 *
+	 * @return bool
+	 */
+	public function is_available();
+
 	/**
 	 * Returns the search_query
 	 *
@@ -142,7 +149,7 @@ interface search_backend_interface
 	/**
 	* Returns an associative array containing information about the indexes
 	*
-	* @return array|bool Language string of error false otherwise
+	* @return array|false Language string of error false otherwise
 	*/
 	public function index_stats();