diff -urN ../z-push-2.5.orig/src/backend/searchcombined/config.php.dist ./src/backend/searchcombined/config.php.dist
--- ../z-push-2.5.orig/src/backend/searchcombined/config.php.dist	1970-01-01 03:00:00.000000000 +0300
+++ ./src/backend/searchcombined/config.php.dist	2023-09-26 16:26:31.987516000 +0300
@@ -0,0 +1,34 @@
+<?php
+/***********************************************
+* File      :   searchcombined/config.php
+* Project   :   Z-Push
+* Descr     :   configuration file for the
+*               BackendSearchCombined backend.
+*
+* Created   :   29.01.2022
+*
+* Copyright 2007 - 2016 Zarafa Deutschland GmbH
+* Copyright 2022        Victor Ustugov corvax+z-push@mta.org.ua
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU Affero General Public License, version 3,
+* as published by the Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* Consult LICENSE file for details
+************************************************/
+
+global $searchcombined_conf;
+$searchcombined_conf = array();
+
+//$searchcombined_conf[] = 'BackendSearchMySQL';
+//$searchcombined_conf[] = 'BackendSearchCardDAV';
+//$searchcombined_conf[] = 'BackendSearchPasswd';
+//$searchcombined_conf[] = 'BackendSearchLDAP';
diff -urN ../z-push-2.5.orig/src/backend/searchcombined/searchcombined.php ./src/backend/searchcombined/searchcombined.php
--- ../z-push-2.5.orig/src/backend/searchcombined/searchcombined.php	1970-01-01 03:00:00.000000000 +0300
+++ ./src/backend/searchcombined/searchcombined.php	2022-01-29 15:58:48.939390000 +0200
@@ -0,0 +1,174 @@
+<?php
+/***********************************************
+* File      :   searchcombined.php
+* Project   :   Z-Push
+* Descr     :   The searchcombined can be used to
+*               implement a combined way perform
+*               searches.
+*               This is a stub implementation.
+*
+* Created   :   29.01.2022
+*
+* Copyright 2007 - 2016 Zarafa Deutschland GmbH
+* Copyright 2022        Victor Ustugov corvax+z-push@mta.org.ua
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU Affero General Public License, version 3,
+* as published by the Free Software Foundation.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU Affero General Public License for more details.
+*
+* You should have received a copy of the GNU Affero General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* Consult LICENSE file for details
+************************************************/
+
+require_once("backend/searchcombined/config.php");
+
+class BackendSearchCombined implements ISearchProvider{
+    static $searchProviders = false;
+
+    /**
+     * Constructor
+     * initializes the searchprovider to perform the search
+     *
+     * @access public
+     * @return
+     * @throws StatusException, FatalException
+     */
+    public function __construct() {
+        global $searchcombined_conf;
+
+        if (!self::$searchProviders) {
+
+            foreach ($searchcombined_conf as $searchClass) {
+                // is a global searchprovider configured ? It will  outrank the backend
+                if ($searchClass) {
+                    if (! class_exists($searchClass))
+                        ZPush::IncludeBackend($searchClass);
+
+                    if (class_exists($searchClass))
+                        $aSearchProvider = new $searchClass();
+                    else
+                        throw new FatalMisconfigurationException(sprintf("BackendSearchCombined(): Search provider '%s' can not be loaded. Check configuration!", $searchClass));
+                }
+                // get the searchprovider from the backend
+                else
+                    $aSearchProvider = ZPush::GetBackend()->GetSearchProvider();
+
+                if (in_array('ISearchProvider', class_implements($aSearchProvider)))
+                    self::$searchProviders[] = $aSearchProvider;
+                else
+                    throw new FatalNotImplementedException("BackendSearchCombined(): Instantiated SearchProvider does not implement the ISearchProvider interface!");
+            }
+        }
+    }
+
+    /**
+     * Indicates if a search type is supported by this SearchProvider
+     * Currently only the type ISearchProvider::SEARCH_GAL (Global Address List) is implemented
+     *
+     * @param string        $searchtype
+     *
+     * @access public
+     * @return boolean
+     */
+    public function SupportsType($searchtype) {
+        return ($searchtype == ISearchProvider::SEARCH_GAL);
+    }
+
+    /**
+     * Searches the GAL
+     *
+     * @param string                        $searchquery        string to be searched for
+     * @param string                        $searchrange        specified searchrange
+     * @param SyncResolveRecipientsPicture  $searchpicture      limitations for picture
+     *
+     * @access public
+     * @return array        search results
+     * @throws StatusException
+     */
+    public function GetGALSearchResults($searchquery, $searchrange, $searchpicture) {
+        if (!self::$searchProviders) {
+            throw new StatusException("BackendSearchCombined(): No search backend defined! Search aborted.", SYNC_SEARCHSTATUS_STORE_CONNECTIONFAILED, null, LOGLEVEL_ERROR);
+        }
+
+        $items = array();
+        foreach (self::$searchProviders as $searchProvider) {
+            $searchProviderItems = $searchProvider->GetGALSearchResults($searchquery, '0-10000', $searchpicture);
+            unset($searchProviderItems['range']);
+            unset($searchProviderItems['searchtotal']);
+            $items = array_merge($items, $searchProviderItems);
+        }
+
+//        ZLog::Write(LOGLEVEL_DEBUG, sprintf("BackendSearchCombined(): got total items: %s", print_r($items, true)));
+
+        $searchtotal = count($items);
+
+        $rangestart = 0;
+        $rangeend = 50;
+        if (!empty($searchrange) and ($searchrange != '0')) {
+            $pos = strpos($searchrange, '-');
+            if ($pos !== false) {
+                $rangestart = substr($searchrange, 0, $pos);
+                $rangeend = substr($searchrange, ($pos + 1));
+            }
+        }
+
+        while (count($items) > $rangeend + 1) array_pop($items);
+        for ($i = 0; $i < $rangestart; $i++) {
+            if (count($items) > 0) array_shift($items);
+        }
+        $items['range'] = $rangestart . '-' . ($rangestart + count($items) - 1);
+        $items['searchtotal'] = $searchtotal;
+
+//        ZLog::Write(LOGLEVEL_DEBUG, sprintf("BackendSearchCombined(): got ranged items: %s", print_r($items, true)));
+
+        return $items;
+    }
+
+    /**
+     * Searches for the emails on the server
+     *
+     * @param ContentParameter $cpo
+     *
+     * @return array
+     */
+    public function GetMailboxSearchResults($cpo){
+        return array();
+    }
+
+    /**
+    * Terminates a search for a given PID
+    *
+    * @param int $pid
+    *
+    * @return boolean
+    */
+    public function TerminateSearch($pid) {
+        return true;
+    }
+
+    /**
+     * Disconnects from the current search provider
+     *
+     * @access public
+     * @return boolean
+     */
+    public function Disconnect() {
+        if (!self::$searchProviders) {
+            throw new StatusException("BackendSearchCombined(): No search backend defined! Search aborted.", SYNC_SEARCHSTATUS_STORE_CONNECTIONFAILED, null, LOGLEVEL_ERROR);
+        }
+
+        $items = array();
+        foreach (self::$searchProviders as $searchProvider) {
+            $searchProvider->Disconnect();
+        }
+
+        return true;
+    }
+}