diff --git a/.tests/lib/BaseDatabaseTestCase.php b/.tests/lib/BaseDatabaseTestCase.php
index 1c38d02..b97c519 100644
--- a/.tests/lib/BaseDatabaseTestCase.php
+++ b/.tests/lib/BaseDatabaseTestCase.php
@@ -1,6 +1,7 @@
 <?php
 
 if (!defined("ROOT_DIR")) { define("ROOT_DIR", __DIR__ . "/../.."); }
+require_once(__DIR__ . "/../../helpers/config.php");
 
 abstract class BaseDatabaseTestCase extends PHPUnit_Extensions_Database_TestCase {
 
@@ -14,6 +15,8 @@ abstract class BaseDatabaseTestCase extends PHPUnit_Extensions_Database_TestCase
   private $conn;
   static private $driver = "mysql";
 
+  protected $mockConfig;
+
   protected $testUser = "testUser";
   protected $testUser2 = "testUser2";
   protected $testAdminUser = "admin";
@@ -44,6 +47,7 @@ abstract class BaseDatabaseTestCase extends PHPUnit_Extensions_Database_TestCase
 
   public function setUp() {
     parent::setUp();
+    $this->mockConfig = new uConfig(false);
   }
 
   public static function setUpBeforeClass() {
diff --git a/.tests/tests/ConfigTest.php b/.tests/tests/ConfigTest.php
index 07779f5..499a01f 100644
--- a/.tests/tests/ConfigTest.php
+++ b/.tests/tests/ConfigTest.php
@@ -6,6 +6,8 @@ require_once(__DIR__ . "/../lib/UloggerDatabaseTestCase.php");
 
 class ConfigTest extends UloggerDatabaseTestCase {
   
+  private $config;
+  
   private $mapApi;
   private $latitude;
   private $longitude;
@@ -26,6 +28,7 @@ class ConfigTest extends UloggerDatabaseTestCase {
 
   public function setUp() {
     parent::setUp();
+    $this->config = uConfig::getInstance();
     $this->initConfigValues();
   }
 
@@ -60,25 +63,75 @@ class ConfigTest extends UloggerDatabaseTestCase {
   }
 
   public function testSetFromDatabase() {
-    uConfig::setFromDatabase();
-    $this->assertEquals($this->mapApi, uConfig::$mapApi);
-    $this->assertEquals($this->latitude, uConfig::$initLatitude);
-    $this->assertEquals($this->longitude, uConfig::$initLongitude);
-    $this->assertEquals($this->googleKey, uConfig::$googleKey);
-    $this->assertEquals($this->requireAuth, uConfig::$requireAuthentication);
-    $this->assertEquals($this->publicTracks, uConfig::$publicTracks);
-    $this->assertEquals($this->passLenMin, uConfig::$passLenMin);
-    $this->assertEquals($this->passStrength, uConfig::$passStrength);
-    $this->assertEquals($this->interval, uConfig::$interval);
-    $this->assertEquals($this->lang, uConfig::$lang);
-    $this->assertEquals($this->units, uConfig::$units);
-    $this->assertEquals($this->strokeWeight, uConfig::$strokeWeight);
-    $this->assertEquals($this->strokeColor, uConfig::$strokeColor);
-    $this->assertEquals($this->strokeOpacity, uConfig::$strokeOpacity);
+    $this->assertEquals($this->mapApi, $this->config->mapApi);
+    $this->assertEquals($this->latitude, $this->config->initLatitude);
+    $this->assertEquals($this->longitude, $this->config->initLongitude);
+    $this->assertEquals($this->googleKey, $this->config->googleKey);
+    $this->assertEquals($this->requireAuth, $this->config->requireAuthentication);
+    $this->assertEquals($this->publicTracks, $this->config->publicTracks);
+    $this->assertEquals($this->passLenMin, $this->config->passLenMin);
+    $this->assertEquals($this->passStrength, $this->config->passStrength);
+    $this->assertEquals($this->interval, $this->config->interval);
+    $this->assertEquals($this->lang, $this->config->lang);
+    $this->assertEquals($this->units, $this->config->units);
+    $this->assertEquals($this->strokeWeight, $this->config->strokeWeight);
+    $this->assertEquals($this->strokeColor, $this->config->strokeColor);
+    $this->assertEquals($this->strokeOpacity, $this->config->strokeOpacity);
 
-    $this->assertEquals($this->testLayer, uConfig::$olLayers[0]->name);
-    $this->assertEquals($this->testUrl, uConfig::$olLayers[0]->url);
-    $this->assertEquals($this->testPriority, uConfig::$olLayers[0]->priority);
+    $this->assertEquals($this->testLayer, $this->config->olLayers[0]->name);
+    $this->assertEquals($this->testUrl, $this->config->olLayers[0]->url);
+    $this->assertEquals($this->testPriority, $this->config->olLayers[0]->priority);
+  }
+
+  public function testSave() {
+    $this->config->mapApi = 'newApi';
+    $this->config->initLatitude = 33.11;
+    $this->config->initLongitude = 22.11;
+    $this->config->googleKey = 'newKey';
+    $this->config->requireAuthentication = false;
+    $this->config->publicTracks = false;
+    $this->config->passLenMin = 31;
+    $this->config->passStrength = 31;
+    $this->config->interval = 661;
+    $this->config->lang = 'newLang';
+    $this->config->units = 'newUnits';
+    $this->config->strokeWeight = 551;
+    $this->config->strokeColor = '#bfbfbf';
+    $this->config->strokeOpacity = 0.11;
+    $this->config->olLayers = [];
+    $this->config->olLayers[0] = new uLayer(11, 'newLayer', 'newUrl', 51);
+
+    $this->config->save();
+
+    $this->assertEquals(1, $this->getConnection()->getRowCount('config'), "Wrong row count");
+    $expected = [
+      "map_api" => $this->config->mapApi,
+      "latitude" => $this->config->initLatitude,
+      "longitude" => $this->config->initLongitude,
+      "google_key" => $this->config->googleKey,
+      "require_auth" => $this->config->requireAuthentication,
+      "public_tracks" => $this->config->publicTracks,
+      "pass_lenmin" => $this->config->passLenMin,
+      "pass_strength" => $this->config->passStrength,
+      "interval_seconds" => $this->config->interval,
+      "lang" => $this->config->lang,
+      "units" => $this->config->units,
+      "stroke_weight" => $this->config->strokeWeight,
+      "stroke_color" => hexdec(str_replace('#', '', $this->config->strokeColor)),
+      "stroke_opacity" => (int) ($this->config->strokeOpacity * 100)
+    ];
+    $actual = $this->getConnection()->createQueryTable("config", "SELECT * FROM config");
+    $this->assertTableContains($expected, $actual, "Wrong actual table data: " . implode(', ', $actual->getRow(0)));
+
+    $this->assertEquals(1, $this->getConnection()->getRowCount('ol_layers'), "Wrong row count");
+    $expected = [
+      "id" => $this->config->olLayers[0]->id,
+      "name" => $this->config->olLayers[0]->name,
+      "url" => $this->config->olLayers[0]->url,
+      "priority" => $this->config->olLayers[0]->priority
+    ];
+    $actual = $this->getConnection()->createQueryTable("ol_layers", "SELECT * FROM ol_layers");
+    $this->assertTableContains($expected, $actual, "Wrong actual table data: " . implode(', ', $actual->getRow(0)));
   }
 
   private function initConfigValues() {
@@ -102,35 +155,35 @@ class ConfigTest extends UloggerDatabaseTestCase {
   }
 
   public function testPassRegex() {
-    uConfig::$passLenMin = 0;
-    uConfig::$passStrength = 0;
+    $this->config->passLenMin = 0;
+    $this->config->passStrength = 0;
     $password0 = "password";
     $password1 = "PASSword";
     $password2 = "PASSword1234";
     $password3 = "PASSword1234-;";
 
-    $regex = uConfig::passRegex();
+    $regex = $this->config->passRegex();
     $this->assertRegExp($regex, $password0, "Regex: \"$regex\", password: \"$password0\"");
     $this->assertRegExp($regex, $password1, "Regex: \"$regex\", password: \"$password1\"");
     $this->assertRegExp($regex, $password2, "Regex: \"$regex\", password: \"$password2\"");
     $this->assertRegExp($regex, $password3, "Regex: \"$regex\", password: \"$password3\"");
 
-    uConfig::$passStrength = 1;
-    $regex = uConfig::passRegex();
+    $this->config->passStrength = 1;
+    $regex = $this->config->passRegex();
     $this->assertNotRegExp($regex, $password0, "Regex: \"$regex\", password: \"$password0\"");
     $this->assertRegExp($regex, $password1, "Regex: \"$regex\", password: \"$password1\"");
     $this->assertRegExp($regex, $password2, "Regex: \"$regex\", password: \"$password2\"");
     $this->assertRegExp($regex, $password3, "Regex: \"$regex\", password: \"$password3\"");
 
-    uConfig::$passStrength = 2;
-    $regex = uConfig::passRegex();
+    $this->config->passStrength = 2;
+    $regex = $this->config->passRegex();
     $this->assertNotRegExp($regex, $password0, "Regex: \"$regex\", password: \"$password0\"");
     $this->assertNotRegExp($regex, $password1, "Regex: \"$regex\", password: \"$password1\"");
     $this->assertRegExp($regex, $password2, "Regex: \"$regex\", password: \"$password2\"");
     $this->assertRegExp($regex, $password3, "Regex: \"$regex\", password: \"$password3\"");
 
-    uConfig::$passStrength = 3;
-    $regex = uConfig::passRegex();
+    $this->config->passStrength = 3;
+    $regex = $this->config->passRegex();
     $this->assertNotRegExp($regex, $password0, "Regex: \"$regex\", password: \"$password0\"");
     $this->assertNotRegExp($regex, $password1, "Regex: \"$regex\", password: \"$password1\"");
     $this->assertNotRegExp($regex, $password2, "Regex: \"$regex\", password: \"$password2\"");
@@ -138,19 +191,19 @@ class ConfigTest extends UloggerDatabaseTestCase {
 
     $password_len5 = "12345";
     $password_len10 = "1234567890";
-    uConfig::$passLenMin = 5;
-    uConfig::$passStrength = 0;
-    $regex = uConfig::passRegex();
+    $this->config->passLenMin = 5;
+    $this->config->passStrength = 0;
+    $regex = $this->config->passRegex();
     $this->assertRegExp($regex, $password_len5, "Regex: \"$regex\", password: \"$password_len5\"");
     $this->assertRegExp($regex, $password_len10, "Regex: \"$regex\", password: \"$password_len10\"");
 
-    uConfig::$passLenMin = 7;
-    $regex = uConfig::passRegex();
+    $this->config->passLenMin = 7;
+    $regex = $this->config->passRegex();
     $this->assertNotRegExp($regex, $password_len5, "Regex: \"$regex\", password: \"$password_len5\"");
     $this->assertRegExp($regex, $password_len10, "Regex: \"$regex\", password: \"$password_len10\"");
 
-    uConfig::$passLenMin = 12;
-    $regex = uConfig::passRegex();
+    $this->config->passLenMin = 12;
+    $regex = $this->config->passRegex();
     $this->assertNotRegExp($regex, $password_len5, "Regex: \"$regex\", password: \"$password_len5\"");
     $this->assertNotRegExp($regex, $password_len10, "Regex: \"$regex\", password: \"$password_len10\"");
   }
diff --git a/.tests/tests/ImportTest.php b/.tests/tests/ImportTest.php
index 1b3dba8..904366a 100644
--- a/.tests/tests/ImportTest.php
+++ b/.tests/tests/ImportTest.php
@@ -626,7 +626,7 @@ class ImportTest extends UloggerAPITestCase {
   }
 
   public function testImportNoLongitude() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $this->assertEquals(0, $this->getConnection()->getRowCount("tracks"), "Wrong row count");
@@ -673,7 +673,7 @@ class ImportTest extends UloggerAPITestCase {
   }
 
   public function testImportNoLatitude() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $this->assertEquals(0, $this->getConnection()->getRowCount("tracks"), "Wrong row count");
@@ -720,7 +720,7 @@ class ImportTest extends UloggerAPITestCase {
   }
 
   public function testImportNoGPX() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $this->assertEquals(0, $this->getConnection()->getRowCount("tracks"), "Wrong row count");
@@ -761,7 +761,7 @@ class ImportTest extends UloggerAPITestCase {
   }
 
   public function testImportCorrupt() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $this->assertEquals(0, $this->getConnection()->getRowCount("tracks"), "Wrong row count");
diff --git a/.tests/tests/InternalAPITest.php b/.tests/tests/InternalAPITest.php
index 6f49c8a..7d5f13c 100644
--- a/.tests/tests/InternalAPITest.php
+++ b/.tests/tests/InternalAPITest.php
@@ -666,7 +666,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleTrackDeleteOtherUser() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
     $this->assertEquals(2, $this->getConnection()->getRowCount("users"), "Wrong row count");
     $this->assertTrue($this->authenticate($this->testUser, $this->testPass), "Authentication failed");
@@ -728,7 +728,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleTrackUpdateEmptyName() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
     $userId = $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
     $this->assertEquals(2, $this->getConnection()->getRowCount("users"), "Wrong row count");
@@ -752,7 +752,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleTrackUpdateNonexistantTrack() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $newName = "New name";
     $this->assertTrue($this->authenticate(), "Authentication failed");
     $userId = $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
@@ -776,7 +776,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleTrackMissingAction() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $options = [
@@ -794,7 +794,7 @@ class InternalAPITest extends UloggerAPITestCase {
   /* handleuser.php */
 
   public function testHandleUserMissingAction() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
 
     $options = [
@@ -809,7 +809,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleUserNonAdmin() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
     $this->assertEquals(2, $this->getConnection()->getRowCount("users"), "Wrong row count");
     $this->assertTrue($this->authenticate($this->testUser, $this->testPass), "Authentication failed");
@@ -829,7 +829,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleUserSelf() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
     $this->assertEquals(1, $this->getConnection()->getRowCount("users"), "Wrong row count");
 
@@ -847,7 +847,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleUserEmptyLogin() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
     $this->assertEquals(1, $this->getConnection()->getRowCount("users"), "Wrong row count");
 
@@ -865,7 +865,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleUserNoAuth() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
     $this->assertEquals(2, $this->getConnection()->getRowCount("users"), "Wrong row count");
 
@@ -908,7 +908,7 @@ class InternalAPITest extends UloggerAPITestCase {
   }
 
   public function testHandleUserAddSameLogin() {
-    $lang = (new uLang("en"))->getStrings();
+    $lang = (new uLang($this->mockConfig))->getStrings();
     $this->assertTrue($this->authenticate(), "Authentication failed");
     $this->addTestUser($this->testUser, password_hash($this->testPass, PASSWORD_DEFAULT));
     $this->assertEquals(2, $this->getConnection()->getRowCount("users"), "Wrong row count");
diff --git a/.tests/tests/LangTest.php b/.tests/tests/LangTest.php
index 4078306..ba2fdee 100644
--- a/.tests/tests/LangTest.php
+++ b/.tests/tests/LangTest.php
@@ -1,11 +1,20 @@
 <?php
 use PHPUnit\Framework\TestCase;
 
+if (!defined("ROOT_DIR")) { define("ROOT_DIR", __DIR__ . "/../.."); }
+
 require_once(__DIR__ . "/../../helpers/config.php");
 require_once(__DIR__ . "/../../helpers/lang.php");
 
 class LangTest extends TestCase {
 
+  protected $mockConfig;
+
+  public function setUp() {
+    parent::setUp();
+    $this->mockConfig = new uConfig(false);
+  }
+
   public function testGetLanguages() {
     $languages = uLang::getLanguages();
     $this->assertNotEmpty($languages);
@@ -16,16 +25,18 @@ class LangTest extends TestCase {
   }
 
   public function testGetStrings() {
-    $lang = new uLang("en");
+    $lang = new uLang($this->mockConfig);
     $this->assertEquals("User", $lang->getStrings()["user"]);
-    $lang = new uLang("pl");
+    $this->mockConfig->lang = "pl";
+    $lang = new uLang($this->mockConfig);
     $this->assertEquals("Użytkownik", $lang->getStrings()["user"]);
   }
 
   public function testGetSetupStrings() {
-    $lang = new uLang("en");
+    $lang = new uLang($this->mockConfig);
     $this->assertEquals("Congratulations!", $lang->getSetupStrings()["congratulations"]);
-    $lang = new uLang("pl");
+    $this->mockConfig->lang = "pl";
+    $lang = new uLang($this->mockConfig);
     $this->assertEquals("Gratulacje!", $lang->getSetupStrings()["congratulations"]);
   }
 }
diff --git a/client/index.php b/client/index.php
index 3de795d..0ce3dc8 100644
--- a/client/index.php
+++ b/client/index.php
@@ -17,125 +17,125 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  /**
-   * Exit with error status and message
-   *
-   * @param string $message Message
-   */
-  function exitWithError($message) {
-    $response = [];
-    $response['error'] = true;
-    $response['message'] = $message;
-    header('Content-Type: application/json');
-    echo json_encode($response);
-    exit();
-  }
+/**
+ * Exit with error status and message
+ *
+ * @param string $message Message
+ */
+function exitWithError($message) {
+  $response = [];
+  $response['error'] = true;
+  $response['message'] = $message;
+  header('Content-Type: application/json');
+  echo json_encode($response);
+  exit();
+}
 
-  /**
-   * Exit with success status
-   *
-   * @param array $params Optional params
-   * @return void
-   */
-  function exitWithSuccess($params = []) {
-    $response = [];
-    $response['error'] = false;
-    header('Content-Type: application/json');
-    echo json_encode(array_merge($response, $params));
-    exit();
-  }
+/**
+ * Exit with success status
+ *
+ * @param array $params Optional params
+ * @return void
+ */
+function exitWithSuccess($params = []) {
+  $response = [];
+  $response['error'] = false;
+  header('Content-Type: application/json');
+  echo json_encode(array_merge($response, $params));
+  exit();
+}
 
-  require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(dirname(__DIR__) . "/helpers/auth.php");
 
-  $action = uUtils::postString('action');
+$action = uUtils::postString('action');
 
-  $auth = new uAuth();
-  if (!$auth->isAuthenticated() && $action != "auth") {
-    $auth->sendUnauthorizedHeader();
-    exitWithError("Unauthorized");
-  }
+$auth = new uAuth();
+if ($action !== "auth" && !$auth->isAuthenticated()) {
+  $auth->sendUnauthorizedHeader();
+  exitWithError("Unauthorized");
+}
 
 switch ($action) {
-    // action: authorize
-    case "auth":
-      $login = uUtils::postString('user');
-      $pass = uUtils::postPass('pass');
-      if ($auth->checkLogin($login, $pass)) {
-        exitWithSuccess();
-      } else {
-        $auth->sendUnauthorizedHeader();
-        exitWithError("Unauthorized");
-      }
-      break;
-
-    // action: adduser (currently unused)
-    case "adduser":
-      if (!$auth->user->isAdmin) {
-        exitWithError("Not allowed");
-      }
-      $login = uUtils::postString('login');
-      $pass = uUtils::postPass('password');
-      if (empty($login) || empty($pass)) {
-        exitWithError("Empty login or password");
-      }
-      $newId = uUser::add($login, $pass);
-      if ($newId === false) {
-        exitWithError("Server error");
-      }
-      exitWithSuccess(['userid'=> $newId]);
-      break;
-
-    // action: addtrack
-    case "addtrack":
-      $trackName = uUtils::postString('track');
-      if (empty($trackName)) {
-        exitWithError("Missing required parameter");
-      }
-      require_once(ROOT_DIR . "/helpers/track.php");
-      $trackId = uTrack::add($auth->user->id, $trackName);
-      if ($trackId === false) {
-        exitWithError("Server error");
-      }
-      // return track id
-      exitWithSuccess(['trackid' => $trackId]);
-      break;
-
-    // action: addposition
-    case "addpos":
-      $lat = uUtils::postFloat('lat');
-      $lon = uUtils::postFloat('lon');
-      $timestamp = uUtils::postInt('time');
-      $altitude = uUtils::postFloat('altitude');
-      $speed = uUtils::postFloat('speed');
-      $bearing = uUtils::postFloat('bearing');
-      $accuracy = uUtils::postInt('accuracy');
-      $provider = uUtils::postString('provider');
-      $comment = uUtils::postString('comment');
-      $imageMeta = uUtils::requestFile('image');
-      $trackId = uUtils::postInt('trackid');
-
-      if (!is_float($lat) || !is_float($lon) || !is_int($timestamp) || !is_int($trackId)) {
-        exitWithError("Missing required parameter");
-      }
-
-      $image = null;
-      if (!empty($imageMeta)) {
-        $image = uUpload::add($imageMeta, $trackId);
-      }
-
-      require_once(ROOT_DIR . "/helpers/position.php");
-      $positionId = uPosition::add($auth->user->id, $trackId,
-              $timestamp, $lat, $lon, $altitude, $speed, $bearing, $accuracy, $provider, $comment, $image);
-
-      if ($positionId === false) {
-        exitWithError("Server error");
-      }
+  // action: authorize
+  case "auth":
+    $login = uUtils::postString('user');
+    $pass = uUtils::postPass('pass');
+    if ($auth->checkLogin($login, $pass)) {
       exitWithSuccess();
-      break;
+    } else {
+      $auth->sendUnauthorizedHeader();
+      exitWithError("Unauthorized");
+    }
+    break;
 
-    default:
-      exitWithError("Unknown command");
-      break;
-  }
+  // action: adduser (currently unused)
+  case "adduser":
+    if (!$auth->user->isAdmin) {
+      exitWithError("Not allowed");
+    }
+    $login = uUtils::postString('login');
+    $pass = uUtils::postPass('password');
+    if (empty($login) || empty($pass)) {
+      exitWithError("Empty login or password");
+    }
+    $newId = uUser::add($login, $pass);
+    if ($newId === false) {
+      exitWithError("Server error");
+    }
+    exitWithSuccess(['userid' => $newId]);
+    break;
+
+  // action: addtrack
+  case "addtrack":
+    $trackName = uUtils::postString('track');
+    if (empty($trackName)) {
+      exitWithError("Missing required parameter");
+    }
+    require_once(ROOT_DIR . "/helpers/track.php");
+    $trackId = uTrack::add($auth->user->id, $trackName);
+    if ($trackId === false) {
+      exitWithError("Server error");
+    }
+    // return track id
+    exitWithSuccess(['trackid' => $trackId]);
+    break;
+
+  // action: addposition
+  case "addpos":
+    $lat = uUtils::postFloat('lat');
+    $lon = uUtils::postFloat('lon');
+    $timestamp = uUtils::postInt('time');
+    $altitude = uUtils::postFloat('altitude');
+    $speed = uUtils::postFloat('speed');
+    $bearing = uUtils::postFloat('bearing');
+    $accuracy = uUtils::postInt('accuracy');
+    $provider = uUtils::postString('provider');
+    $comment = uUtils::postString('comment');
+    $imageMeta = uUtils::requestFile('image');
+    $trackId = uUtils::postInt('trackid');
+
+    if (!is_float($lat) || !is_float($lon) || !is_int($timestamp) || !is_int($trackId)) {
+      exitWithError("Missing required parameter");
+    }
+
+    $image = null;
+    if (!empty($imageMeta)) {
+      $image = uUpload::add($imageMeta, $trackId);
+    }
+
+    require_once(ROOT_DIR . "/helpers/position.php");
+    $positionId = uPosition::add($auth->user->id, $trackId,
+      $timestamp, $lat, $lon, $altitude, $speed, $bearing, $accuracy, $provider, $comment, $image);
+
+    if ($positionId === false) {
+      exitWithError("Server error");
+    }
+    exitWithSuccess();
+    break;
+
+  default:
+    exitWithError("Unknown command");
+    break;
+}
 
 ?>
\ No newline at end of file
diff --git a/helpers/auth.php b/helpers/auth.php
index afe9f78..a4f2e4f 100644
--- a/helpers/auth.php
+++ b/helpers/auth.php
@@ -30,12 +30,12 @@
     /** @var bool Is user authenticated */
     private $isAuthenticated = false;
     /** @var null|uUser */
-    public $user = null;
+    public $user;
 
     public function __construct() {
       $this->sessionStart();
 
-      $user = (new uUser())->getFromSession();
+      $user = uUser::getFromSession();
       if ($user->isValid) {
         $this->setAuthenticated($user);
       }
diff --git a/helpers/config.php b/helpers/config.php
index 8c12abd..8700972 100644
--- a/helpers/config.php
+++ b/helpers/config.php
@@ -20,75 +20,60 @@
 require_once(ROOT_DIR . "/helpers/db.php");
 require_once(ROOT_DIR . "/helpers/layer.php");
 
-/**
- * Initialize on file include
- */
-uConfig::init();
 
 /**
  * Handles config values
  */
 class uConfig {
+  /**
+   * Singleton instance
+   *
+   * @var uConfig Object instance
+   */
+  private static $instance;
   /**
    * @var string Version number
    */
-  public static $version = "1.0-beta";
+  public $version = "1.0-beta";
 
   /**
    * @var string Default map drawing framework
    */
-  public static $mapApi = "openlayers";
+  public $mapApi = "openlayers";
 
   /**
    * @var string|null Google maps key
    */
-  public static $googleKey;
+  public $googleKey;
 
   /**
    * @var uLayer[] Openlayers extra map layers
    */
-  public static $olLayers = [];
+  public $olLayers = [];
 
   /**
    * @var float Default latitude for initial map
    */
-  public static $initLatitude = 52.23;
+  public $initLatitude = 52.23;
   /**
    * @var float Default longitude for initial map
    */
-  public static $initLongitude = 21.01;
-
-  /**
-   * @var string Database DSN
-   */
-  public static $dbdsn = "";
-  /**
-   * @var string Database user
-   */
-  public static $dbuser = "";
-  /**
-   * @var string Database pass
-   */
-  public static $dbpass = "";
-  /**
-   * @var string Optional table names prefix, eg. "ulogger_"
-   */
-  public static $dbprefix = "";
+  public $initLongitude = 21.01;
 
   /**
    * @var bool Require login/password authentication
    */
-  public static $requireAuthentication = true;
+  public $requireAuthentication = true;
 
   /**
    * @var bool All users tracks are visible to authenticated user
    */
-  public static $publicTracks = false;
+  public $publicTracks = false;
 
   /**
    * @var int Miniumum required length of user password
    */
-  public static $passLenMin = 10;
+  public $passLenMin = 10;
 
   /**
    * @var int Required strength of user password
@@ -97,49 +82,65 @@ class uConfig {
    * 2 = require mixed case and numbers
    * 3 = require mixed case, numbers and non-alphanumeric characters
    */
-  public static $passStrength = 2;
+  public $passStrength = 2;
 
   /**
    * @var int Default interval in seconds for live auto reload
    */
-  public static $interval = 10;
+  public $interval = 10;
 
   /**
    * @var string Default language code
    */
-  public static $lang = "en";
+  public $lang = "en";
 
   /**
    * @var string Default units
    */
-  public static $units = "metric";
+  public $units = "metric";
 
   /**
    * @var int Stroke weight
    */
-  public static $strokeWeight = 2;
+  public $strokeWeight = 2;
   /**
    * @var string Stroke color
    */
-  public static $strokeColor = '#ff0000';
+  public $strokeColor = '#ff0000';
   /**
-   * @var int Stroke opacity
+   * @var float Stroke opacity
    */
-  public static $strokeOpacity = 1;
-
-  private static $fileLoaded = false;
-  private static $initialized = false;
-
-  /**
-   * Static initializer
-   */
-  public static function init() {
-    if (!self::$initialized) {
-      self::setFromFile();
-      self::setFromDatabase();
-      self::setFromCookies();
-      self::$initialized = true;
+  public $strokeOpacity = 1.0;
+  
+  public function __construct($useDatabase = true) {
+    if ($useDatabase) {
+      $this->setFromDatabase();
     }
+    $this->setFromCookies();
+  }
+
+  /**
+   * Returns singleton instance
+   *
+   * @return uConfig Singleton instance
+   */
+  public static function getInstance() {
+    if (!self::$instance) {
+      self::$instance = new self();
+    }
+    return self::$instance;
+  }
+
+  /**
+   * Returns singleton instance
+   *
+   * @return uConfig Singleton instance
+   */
+  public static function getOfflineInstance() {
+    if (!self::$instance) {
+      self::$instance = new self(false);
+    }
+    return self::$instance;
   }
 
   /**
@@ -154,7 +155,7 @@ class uConfig {
   /**
    * Read config values from database
    */
-  public static function setFromDatabase() {
+  public function setFromDatabase() {
     try {
       $query = "SELECT map_api, latitude, longitude, google_key, require_auth, public_tracks, 
                        pass_lenmin, pass_strength, interval_seconds, lang, units, 
@@ -163,30 +164,91 @@ class uConfig {
       $result = self::db()->query($query);
       $row = $result->fetch();
       if ($row) {
-        if (!empty($row['map_api'])) { self::$mapApi = $row['map_api']; }
-        if (is_numeric($row['latitude'])) { self::$initLatitude = $row['latitude']; }
-        if (is_numeric($row['longitude'])) { self::$initLongitude = $row['longitude']; }
-        if (!empty($row['google_key'])) { self::$googleKey = $row['google_key']; }
-        if (is_numeric($row['require_auth']) || is_bool($row['require_auth'])) { self::$requireAuthentication = (bool) $row['require_auth']; }
-        if (is_numeric($row['public_tracks']) || is_bool($row['public_tracks'])) { self::$publicTracks = (bool) $row['public_tracks']; }
-        if (is_numeric($row['pass_lenmin'])) { self::$passLenMin = $row['pass_lenmin']; }
-        if (is_numeric($row['pass_strength'])) { self::$passStrength = $row['pass_strength']; }
-        if (is_numeric($row['interval_seconds'])) { self::$interval = $row['interval_seconds']; }
-        if (!empty($row['lang'])) { self::$lang = $row['lang']; }
-        if (!empty($row['units'])) { self::$units = $row['units']; }
-        if (is_numeric($row['stroke_weight'])) { self::$strokeWeight = $row['stroke_weight']; }
-        if (is_numeric($row['stroke_color'])) { self::$strokeColor = self::getColorAsHex($row['stroke_color']); }
-        if (is_numeric($row['stroke_opacity'])) { self::$strokeOpacity = $row['stroke_opacity'] / 100; }
+        if (!empty($row['map_api'])) { $this->mapApi = $row['map_api']; }
+        if (is_numeric($row['latitude'])) { $this->initLatitude = (float) $row['latitude']; }
+        if (is_numeric($row['longitude'])) { $this->initLongitude = (float) $row['longitude']; }
+        if (!empty($row['google_key'])) { $this->googleKey = $row['google_key']; }
+        if (is_numeric($row['require_auth']) || is_bool($row['require_auth'])) { $this->requireAuthentication = (bool) $row['require_auth']; }
+        if (is_numeric($row['public_tracks']) || is_bool($row['public_tracks'])) { $this->publicTracks = (bool) $row['public_tracks']; }
+        if (is_numeric($row['pass_lenmin'])) { $this->passLenMin = (int) $row['pass_lenmin']; }
+        if (is_numeric($row['pass_strength'])) { $this->passStrength = (int) $row['pass_strength']; }
+        if (is_numeric($row['interval_seconds'])) { $this->interval = (int) $row['interval_seconds']; }
+        if (!empty($row['lang'])) { $this->lang = $row['lang']; }
+        if (!empty($row['units'])) { $this->units = $row['units']; }
+        if (is_numeric($row['stroke_weight'])) { $this->strokeWeight = (int) $row['stroke_weight']; }
+        if (is_numeric($row['stroke_color'])) { $this->strokeColor = self::getColorAsHex($row['stroke_color']); }
+        if (is_numeric($row['stroke_opacity'])) { $this->strokeOpacity = $row['stroke_opacity'] / 100; }
       }
-      self::setLayersFromDatabase();
-      if (!self::$requireAuthentication) {
+      $this->setLayersFromDatabase();
+      if (!$this->requireAuthentication) {
         // tracks must be public if we don't require authentication
-        self::$publicTracks = true;
+        $this->publicTracks = true;
       }
     } catch (PDOException $e) {
       // TODO: handle exception
       syslog(LOG_ERR, $e->getMessage());
-      return;
+    }
+  }
+
+  /**
+   * Save config values to database
+   * @return bool True on success, false otherwise
+   */
+  public function save() {
+    $ret = false;
+    try {
+      $query = "UPDATE " . self::db()->table('config') . "
+                SET map_api = ?, latitude = ?, longitude = ?, google_key = ?, require_auth = ?, public_tracks = ?, 
+                    pass_lenmin = ?, pass_strength = ?, interval_seconds = ?, lang = ?, units = ?, 
+                    stroke_weight = ?, stroke_color = ?, stroke_opacity = ?";
+      $stmt = self::db()->prepare($query);
+      $params = [
+        $this->mapApi,
+        $this->initLatitude,
+        $this->initLongitude,
+        $this->googleKey,
+        (int) $this->requireAuthentication,
+        (int) $this->publicTracks,
+        $this->passLenMin,
+        $this->passStrength,
+        $this->interval,
+        $this->lang,
+        $this->units,
+        $this->strokeWeight,
+        self::getColorAsInt($this->strokeColor),
+        (int) ($this->strokeOpacity * 100)
+      ];
+      $stmt->execute($params);
+      $this->saveLayers();
+      $ret = true;
+    } catch (PDOException $e) {
+      // TODO: handle exception
+      syslog(LOG_ERR, $e->getMessage());
+    }
+    return $ret;
+  }
+
+  /**
+   * Truncate ol_layers table
+   * @throws PDOException
+   */
+  private function deleteLayers() {
+    $query = "DELETE FROM " . self::db()->table('ol_layers');
+    self::db()->exec($query);
+  }
+
+  /**
+   * Save layers to database
+   * @throws PDOException
+   */
+  private function saveLayers() {
+    $this->deleteLayers();
+    if (!empty($this->olLayers)) {
+      $query = "INSERT INTO " . self::db()->table('ol_layers') . " (id, name, url, priority) VALUES (?, ?, ?, ?)";
+      $stmt = self::db()->prepare($query);
+      foreach ($this->olLayers as $layer) {
+        $stmt->execute([ $layer->id, $layer->name, $layer->url, $layer->priority]);
+      }
     }
   }
 
@@ -194,50 +256,34 @@ class uConfig {
    * Read config values from database
    * @throws PDOException
    */
-  private static function setLayersFromDatabase() {
-    self::$olLayers = [];
+  private function setLayersFromDatabase() {
+    $this->olLayers = [];
     $query = "SELECT id, name, url, priority FROM " . self::db()->table('ol_layers');
     $result = self::db()->query($query);
     while ($row = $result->fetch()) {
-      self::$olLayers[] = new uLayer($row['id'], $row['name'], $row['url'], $row['priority']);
+      $this->olLayers[] = new uLayer($row['id'], $row['name'], $row['url'], $row['priority']);
     }
   }
 
-  /**
-   * Read config values from "/config.php" file
-   * @noinspection IssetArgumentExistenceInspection
-   * @noinspection DuplicatedCode
-   * @noinspection PhpIncludeInspection
-   */
-  private static function setFromFile() {
-    $configFile = ROOT_DIR . "/config.php";
-    if (self::$fileLoaded || !file_exists($configFile)) { return; }
-    self::$fileLoaded = true;
-    include_once($configFile);
-
-    if (isset($dbdsn)) { self::$dbdsn = $dbdsn; }
-    if (isset($dbuser)) { self::$dbuser = $dbuser; }
-    if (isset($dbpass)) { self::$dbpass = $dbpass; }
-    if (isset($dbprefix)) { self::$dbprefix = $dbprefix; }
-  }
-
   /**
    * Read config values stored in cookies
    */
-  private static function setFromCookies() {
-    if (isset($_COOKIE["ulogger_api"])) { self::$mapApi = $_COOKIE["ulogger_api"]; }
-    if (isset($_COOKIE["ulogger_lang"])) { self::$lang = $_COOKIE["ulogger_lang"]; }
-    if (isset($_COOKIE["ulogger_units"])) { self::$units = $_COOKIE["ulogger_units"]; }
-    if (isset($_COOKIE["ulogger_interval"])) { self::$interval = $_COOKIE["ulogger_interval"]; }
+  private function setFromCookies() {
+    if (isset($_COOKIE["ulogger_api"])) { $this->mapApi = $_COOKIE["ulogger_api"]; }
+    if (isset($_COOKIE["ulogger_lang"])) { $this->lang = $_COOKIE["ulogger_lang"]; }
+    if (isset($_COOKIE["ulogger_units"])) { $this->units = $_COOKIE["ulogger_units"]; }
+    if (isset($_COOKIE["ulogger_interval"])) { $this->interval = $_COOKIE["ulogger_interval"]; }
   }
 
+
   /**
-   * Is config loaded from file?
+   * Check if given password matches user's one
    *
-   * @return bool True if loaded, false otherwise
+   * @param String $password Password
+   * @return bool True if matches, false otherwise
    */
-  public static function isFileLoaded() {
-    return self::$fileLoaded;
+  public function validPassStrength($password) {
+    return preg_match($this->passRegex(), $password);
   }
 
   /**
@@ -245,22 +291,22 @@ class uConfig {
    * Valid for both php and javascript
    * @return string
    */
-  public static function passRegex() {
+  public function passRegex() {
     $regex = "";
-    if (self::$passStrength > 0) {
+    if ($this->passStrength > 0) {
       // lower and upper case
       $regex .= "(?=.*[a-z])(?=.*[A-Z])";
     }
-    if (self::$passStrength > 1) {
+    if ($this->passStrength > 1) {
       // digits
       $regex .= "(?=.*[0-9])";
     }
-    if (self::$passStrength > 2) {
+    if ($this->passStrength > 2) {
       // not latin, not digits
       $regex .= "(?=.*[^a-zA-Z0-9])";
     }
-    if (self::$passLenMin > 0) {
-      $regex .= "(?=.{" . self::$passLenMin . ",})";
+    if ($this->passLenMin > 0) {
+      $regex .= "(?=.{" . $this->passLenMin . ",})";
     }
     if (empty($regex)) {
       $regex = ".*";
diff --git a/helpers/db.php b/helpers/db.php
index 71bc962..fc8015e 100644
--- a/helpers/db.php
+++ b/helpers/db.php
@@ -17,8 +17,6 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  require_once(ROOT_DIR . "/helpers/config.php");
-
  /**
   * PDO wrapper
   */
@@ -44,6 +42,23 @@
      */
     protected static $driver;
 
+    /**
+     * @var string Database DSN
+     */
+    private static $dbdsn = "";
+    /**
+     * @var string Database user
+     */
+    private static $dbuser = "";
+    /**
+     * @var string Database pass
+     */
+    private static $dbpass = "";
+    /**
+     * @var string Optional table names prefix, eg. "ulogger_"
+     */
+    private static $dbprefix = "";
+
    /**
     * PDO constuctor
     *
@@ -73,7 +88,7 @@
      */
     private function initTables() {
       self::$tables = [];
-      $prefix = preg_replace('/[^a-z0-9_]/i', '', uConfig::$dbprefix);
+      $prefix = preg_replace('/[^a-z0-9_]/i', '', self::$dbprefix);
       self::$tables['positions'] = $prefix . "positions";
       self::$tables['tracks'] = $prefix . "tracks";
       self::$tables['users'] = $prefix . "users";
@@ -88,12 +103,39 @@
     */
     public static function getInstance() {
       if (!self::$instance) {
-        self::$instance = new self(uConfig::$dbdsn, uConfig::$dbuser, uConfig::$dbpass);
+        self::getConfig();
+        self::$instance = new self(self::$dbdsn, self::$dbuser, self::$dbpass);
       }
       return self::$instance;
     }
 
-   /**
+    /**
+     * Read database setup from config file
+     * @noinspection IssetArgumentExistenceInspection
+     * @noinspection PhpIncludeInspection
+     */
+    private static function getConfig() {
+      $configFile = dirname(__DIR__) . "/config.php";
+      if (!file_exists($configFile)) {
+        header("HTTP/1.1 503 Service Unavailable");
+        die("Missing config.php file!");
+      }
+      include($configFile);
+      if (isset($dbdsn)) {
+        self::$dbdsn = $dbdsn;
+      }
+      if (isset($dbuser)) {
+        self::$dbuser = $dbuser;
+      }
+      if (isset($dbpass)) {
+        self::$dbpass = $dbpass;
+      }
+      if (isset($dbprefix)) {
+        self::$dbprefix = $dbprefix;
+      }
+    }
+
+    /**
     * Get full table name including prefix
     *
     * @param string $name Name
diff --git a/helpers/lang.php b/helpers/lang.php
index f9a276b..0f97c0c 100644
--- a/helpers/lang.php
+++ b/helpers/lang.php
@@ -61,9 +61,10 @@
     /**
      * Constructor
      *
-     * @param string $language Language code (IANA)
+     * @param uConfig $config Config
      */
-    public function __construct($language = "en") {
+    public function __construct($config) {
+      $language = $config->lang;
       $lang = [];
       $langSetup = [];
       // always load en base
@@ -76,9 +77,9 @@
       }
 
       // choose password messages based on config
-      $passRules = "passrules_" . uConfig::$passStrength;
+      $passRules = "passrules_" . $config->passStrength;
       $lang['passrules'] = isset($lang[$passRules]) ? $lang[$passRules] : "";
-      $lang['passlenmin'] = sprintf($lang["passlenmin"], uConfig::$passLenMin);
+      $lang['passlenmin'] = sprintf($lang["passlenmin"], $config->passLenMin);
       $this->strings = $lang;
       $this->setupStrings = $langSetup;
     }
diff --git a/helpers/user.php b/helpers/user.php
index 30c160d..9a3e3bb 100644
--- a/helpers/user.php
+++ b/helpers/user.php
@@ -16,7 +16,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
-  require_once(ROOT_DIR . "/helpers/config.php");
   require_once(ROOT_DIR . "/helpers/db.php");
   require_once(ROOT_DIR . "/helpers/track.php");
   require_once(ROOT_DIR . "/helpers/position.php");
@@ -75,7 +74,7 @@
      */
     public static function add($login, $pass, $isAdmin = false) {
       $userid = false;
-      if (!empty($login) && !empty($pass) && self::validPassStrength($pass)) {
+      if (!empty($login) && !empty($pass)) {
         $hash = password_hash($pass, PASSWORD_DEFAULT);
         $table = self::db()->table('users');
         try {
@@ -152,7 +151,7 @@
     */
     public function setPass($pass) {
       $ret = false;
-      if (!empty($this->login) && !empty($pass) && self::validPassStrength($pass)) {
+      if (!empty($this->login) && !empty($pass)) {
         $hash = password_hash($pass, PASSWORD_DEFAULT);
         try {
           $query = "UPDATE " . self::db()->table('users') . " SET password = ? WHERE login = ?";
@@ -178,16 +177,6 @@
       return password_verify($password, $this->hash);
     }
 
-   /**
-    * Check if given password matches user's one
-    *
-    * @param String $password Password
-    * @return bool True if matches, false otherwise
-    */
-    private static function validPassStrength($password) {
-      return preg_match(uConfig::passRegex(), $password);
-    }
-
    /**
     * Store uUser object in session
     */
@@ -199,16 +188,17 @@
     * Fill uUser object properties from session data
     * @return uUser
     */
-    public function getFromSession() {
+    public static function getFromSession() {
+      $user = new uUser();
       if (isset($_SESSION['user'])) {
         $sessionUser = $_SESSION['user'];
-        $this->id = $sessionUser->id;
-        $this->login = $sessionUser->login;
-        $this->hash = $sessionUser->hash;
-        $this->isAdmin = $sessionUser->isAdmin;
-        $this->isValid = $sessionUser->isValid;
+        $user->id = $sessionUser->id;
+        $user->login = $sessionUser->login;
+        $user->hash = $sessionUser->hash;
+        $user->isAdmin = $sessionUser->isAdmin;
+        $user->isValid = $sessionUser->isValid;
       }
-      return $this;
+      return $user;
     }
 
    /**
diff --git a/index.php b/index.php
index f05dd67..55c3ebd 100644
--- a/index.php
+++ b/index.php
@@ -28,7 +28,8 @@
   $pass = uUtils::postPass('pass');
   $action = uUtils::postString('action');
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+  $config = uConfig::getInstance();
+  $lang = (new uLang($config))->getStrings();
   $langsArr = uLang::getLanguages();
 
   $auth = new uAuth();
@@ -39,13 +40,13 @@
   if ($action === 'auth' && !$auth->isAuthenticated()) {
     $auth->exitWithRedirect('login.php?auth_error=1');
   }
-  if (uConfig::$requireAuthentication && !$auth->isAuthenticated()) {
+  if ($config->requireAuthentication && !$auth->isAuthenticated()) {
     $auth->exitWithRedirect('login.php');
   }
 
 ?>
 <!DOCTYPE html>
-<html lang="<?= uConfig::$lang ?>">
+<html lang="<?= $config->lang ?>">
   <head>
     <title><?= $lang['title'] ?></title>
     <?php include('meta.php'); ?>
@@ -78,7 +79,7 @@
             <label for="track"><?= $lang['track'] ?></label>
             <select id="track" data-bind="currentTrackId" name="track"></select>
             <input id="latest" type="checkbox" data-bind="showLatest"> <label for="latest"><?= $lang['latest'] ?></label><br>
-            <input id="auto-reload" type="checkbox" data-bind="autoReload"> <label for="auto-reload"><?= $lang['autoreload'] ?></label> (<a id="set-interval" data-bind="onSetInterval"><span id="interval" data-bind="interval"><?= uConfig::$interval ?></span></a> s)<br>
+            <input id="auto-reload" type="checkbox" data-bind="autoReload"> <label for="auto-reload"><?= $lang['autoreload'] ?></label> (<a id="set-interval" data-bind="onSetInterval"><span id="interval" data-bind="interval"><?= $config->interval ?></span></a> s)<br>
             <a id="force-reload" data-bind="onReload"> <?= $lang['reload'] ?></a><br>
           </div>
 
@@ -91,8 +92,8 @@
           <div>
             <label for="api"><?= $lang['api'] ?></label>
             <select id="api" name="api" data-bind="mapApi">
-              <option value="gmaps"<?= (uConfig::$mapApi === 'gmaps') ? ' selected' : '' ?>>Google Maps</option>
-              <option value="openlayers"<?= (uConfig::$mapApi === 'openlayers') ? ' selected' : '' ?>>OpenLayers</option>
+              <option value="gmaps"<?= ($config->mapApi === 'gmaps') ? ' selected' : '' ?>>Google Maps</option>
+              <option value="openlayers"<?= ($config->mapApi === 'openlayers') ? ' selected' : '' ?>>OpenLayers</option>
             </select>
           </div>
 
@@ -100,7 +101,7 @@
             <label for="lang"><?= $lang['language'] ?></label>
             <select id="lang" name="lang" data-bind="lang">
               <?php foreach ($langsArr as $langCode => $langName): ?>
-                <option value="<?= $langCode ?>"<?= (uConfig::$lang === $langCode) ? ' selected' : '' ?>><?= $langName ?></option>
+                <option value="<?= $langCode ?>"<?= ($config->lang === $langCode) ? ' selected' : '' ?>><?= $langName ?></option>
               <?php endforeach; ?>
             </select>
           </div>
@@ -108,9 +109,9 @@
           <div class="section">
             <label for="units"><?= $lang['units'] ?></label>
             <select id="units" name="units" data-bind="units">
-              <option value="metric"<?= (uConfig::$units === 'metric') ? ' selected' : '' ?>><?= $lang['metric'] ?></option>
-              <option value="imperial"<?= (uConfig::$units === 'imperial') ? ' selected' : '' ?>><?= $lang['imperial'] ?></option>
-              <option value="nautical"<?= (uConfig::$units === 'nautical') ? ' selected' : '' ?>><?= $lang['nautical'] ?></option>
+              <option value="metric"<?= ($config->units === 'metric') ? ' selected' : '' ?>><?= $lang['metric'] ?></option>
+              <option value="imperial"<?= ($config->units === 'imperial') ? ' selected' : '' ?>><?= $lang['imperial'] ?></option>
+              <option value="nautical"<?= ($config->units === 'nautical') ? ' selected' : '' ?>><?= $lang['nautical'] ?></option>
             </select>
           </div>
 
@@ -142,7 +143,7 @@
 
         </div>
         <div id="menu-button"><a data-bind="onMenuToggle"></a></div>
-        <div id="footer"><a target="_blank" href="https://github.com/bfabiszewski/ulogger-server"><span class="mi">μ</span>logger</a> <?= uConfig::$version ?></div>
+        <div id="footer"><a target="_blank" href="https://github.com/bfabiszewski/ulogger-server"><span class="mi">μ</span>logger</a> <?= $config->version ?></div>
       </div>
 
       <div id="main">
diff --git a/login.php b/login.php
index 6cd16eb..92072e5 100644
--- a/login.php
+++ b/login.php
@@ -23,11 +23,12 @@
 
   $auth_error = uUtils::getBool('auth_error', false);
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+  $config = uConfig::getInstance();
+  $lang = (new uLang($config))->getStrings();
 
 ?>
 <!DOCTYPE html>
-<html lang="<?= uConfig::$lang ?>">
+<html lang="<?= $config->lang ?>">
   <head>
     <title><?= $lang["title"] ?></title>
     <?php include("meta.php"); ?>
@@ -49,7 +50,7 @@
         <br>
         <input type="submit" value="<?= $lang["login"] ?>">
         <input type="hidden" name="action" value="auth">
-        <?php if (!uConfig::$requireAuthentication): ?>
+        <?php if (!$config->requireAuthentication): ?>
           <div id="cancel"><a href="<?= BASE_URL ?>"><?= $lang["cancel"] ?></a></div>
         <?php endif; ?>
       </form>
diff --git a/scripts/import_cli.php b/scripts/import_cli.php
index 215a790..1c63ba1 100644
--- a/scripts/import_cli.php
+++ b/scripts/import_cli.php
@@ -33,7 +33,7 @@ if (file_exists(ROOT_DIR . '/vendor/autoload.php')) {
 }
 
 // check we are running in CLI mode
-if (PHP_SAPI != 'cli') {
+if (PHP_SAPI !== 'cli') {
   exit('Call me on CLI only!' . PHP_EOL);
 }
 
@@ -90,7 +90,9 @@ if (!$getopt->getOption('import-existing-track')) {
 $gpxFiles = $getopt->getOperand('gpx');
 foreach ($gpxFiles as $i => $gpxFile) {
   // skip last track?
-  if ($getopt->getOption('skip-last-track') && $i === count($gpxFiles) - 1) continue;
+  if ($getopt->getOption('skip-last-track') && $i === count($gpxFiles) - 1) {
+    continue;
+  }
 
   $gpxName = basename($gpxFile);
 
@@ -105,7 +107,8 @@ foreach ($gpxFiles as $i => $gpxFile) {
 
   print('importing ' . $gpxFile.'...' . PHP_EOL);
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+  $config = uConfig::getInstance();
+  $lang = (new uLang($config))->getStrings();
 
   $gpx = false;
   libxml_use_internal_errors(true);
@@ -125,8 +128,8 @@ foreach ($gpxFiles as $i => $gpxFile) {
     }
     uUtils::exitWithError($message);
   }
-  else if ($gpx->getName() != "gpx") {
-      uUtils::exitWithError($lang["iparsefailure"]);
+  else if ($gpx->getName() !== "gpx") {
+    uUtils::exitWithError($lang["iparsefailure"]);
   }
   else if (empty($gpx->trk)) {
     uUtils::exitWithError($lang["idatafailure"]);
@@ -165,8 +168,8 @@ foreach ($gpxFiles as $i => $gpxFile) {
           if (count($ext->provider)) { $provider = (string) $ext->provider; }
         }
         $ret = $track->addPosition($userId,
-                      $time, (double) $point["lat"], (double) $point["lon"], $altitude,
-                      $speed, $bearing, $accuracy, $provider, NULL, NULL);
+          $time, (double) $point["lat"], (double) $point["lon"], $altitude,
+          $speed, $bearing, $accuracy, $provider, NULL, NULL);
         if ($ret === false) {
           $track->delete();
           uUtils::exitWithError($lang["servererror"]);
diff --git a/scripts/setup.php b/scripts/setup.php
index 7773a80..578b3ca 100644
--- a/scripts/setup.php
+++ b/scripts/setup.php
@@ -30,6 +30,21 @@ if (version_compare(PHP_VERSION, "5.5.0", "<")) {
 }
 
 define("ROOT_DIR", dirname(__DIR__));
+$dbConfig = ROOT_DIR . "/config.php";
+$dbConfigLoaded = false;
+$configDSN = "";
+$configUser = "";
+$configPass = "";
+$configPrefix = "";
+if (file_exists($dbConfig)) {
+  /** @noinspection PhpIncludeInspection */
+  include($dbConfig);
+  $dbConfigLoaded = true;
+  if (isset($dbdsn)) { $configDSN = $dbdsn; }
+  if (isset($dbuser)) { $configUser = $dbuser; }
+  if (isset($dbpass)) { $configPass = $dbpass; }
+  if (isset($dbprefix)) { $configPrefix = $dbprefix; }
+}
 require_once(ROOT_DIR . "/helpers/db.php");
 require_once(ROOT_DIR . "/helpers/config.php");
 require_once(ROOT_DIR . "/helpers/lang.php");
@@ -37,11 +52,14 @@ require_once(ROOT_DIR . "/helpers/user.php");
 require_once(ROOT_DIR . "/helpers/utils.php");
 
 $command = uUtils::postString("command");
+$language = uUtils::getString("lang", "en");
 
-$lang = (new uLang(uConfig::$lang))->getStrings();
-$langSetup = (new uLang(uConfig::$lang))->getSetupStrings();
+$config = uConfig::getOfflineInstance();
+$config->lang = $language;
+$lang = (new uLang($config))->getStrings();
+$langSetup = (new uLang($config))->getSetupStrings();
 
-$prefix = preg_replace("/[^a-z0-9_]/i", "", uConfig::$dbprefix);
+$prefix = preg_replace("/[^a-z0-9_]/i", "", $configPrefix);
 $tPositions = $prefix . "positions";
 $tTracks = $prefix . "tracks";
 $tUsers = $prefix . "users";
@@ -79,7 +97,7 @@ switch ($command) {
     if (!$error) {
       $messages[] = "<span class=\"ok\">{$langSetup["dbtablessuccess"]}</span>";
       $messages[] = $langSetup["setupuser"];
-      $form = "<form id=\"userForm\" method=\"post\" action=\"setup.php\" onsubmit=\"return validateForm()\"><input type=\"hidden\" name=\"command\" value=\"adduser\">";
+      $form = "<form id=\"userForm\" method=\"post\" action=\"setup.php?lang=$language\" onsubmit=\"return validateForm()\"><input type=\"hidden\" name=\"command\" value=\"adduser\">";
       $form .= "<label><b>{$lang["username"]}</b></label><input type=\"text\" placeholder=\"{$lang["usernameenter"]}\" name=\"login\" required>";
       $form .= "<label><b>{$lang["password"]}</b></label><input type=\"password\" placeholder=\"{$lang["passwordenter"]}\" name=\"pass\" required>";
       $form .= "<label><b>{$lang["passwordrepeat"]}</b></label><input type=\"password\" placeholder=\"{$lang["passwordenter"]}\" name=\"pass2\" required>";
@@ -90,6 +108,7 @@ switch ($command) {
     break;
 
   case "adduser":
+    $config->save();
     $login = uUtils::postString("login");
     $pass = uUtils::postPass("pass");
 
@@ -104,43 +123,54 @@ switch ($command) {
     break;
 
   default:
+    $langsArr = uLang::getLanguages();
+    $langsOpts = "";
+    foreach ($langsArr as $langCode => $langName) {
+      $langsOpts .= "<option value=\"$langCode\"" . ($config->lang === $langCode ? " selected" : "") . ">$langName</option>";
+    }
+    $messages[] = "<div id=\"language\">
+      <label for=\"lang\">{$lang['language']}</label>
+      <select id=\"lang\" name=\"lang\" onchange=\"return changeLang(this)\">
+        $langsOpts
+      </select>
+    </div>";
     $messages[] = "<img src=\"../icons/favicon-32x32.png\" alt=\"µLogger\">" . $langSetup["welcome"];
     if (!isset($enabled) || $enabled === false) {
       $messages[] = sprintf($langSetup["disabledwarn"], "<b>\$enabled</b>", "<b>true</b>");
       $messages[] = sprintf($langSetup["lineshouldread"], "<br><span class=\"warn\">\$enabled = false;</span><br>", "<br><span class=\"ok\">\$enabled = true;</span>");
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
-    if (!uConfig::isFileLoaded()) {
+    if (!$dbConfigLoaded) {
       $messages[] = $langSetup["createconfig"];
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
     if (ini_get("session.auto_start") === "1") {
       $messages[] = sprintf($langSetup["optionwarn"], "session.auto_start", "0 (off)");
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
     if (!extension_loaded("pdo")) {
       $messages[] = sprintf($langSetup["extensionwarn"], "PDO");
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
-    if (empty(uConfig::$dbdsn)) {
+    if (empty($configDSN)) {
       $messages[] = sprintf($langSetup["nodbsettings"], "\$dbdsn");
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
     try {
       $pdo = getPdo();
     } catch (PDOException $e) {
-      $isSqlite = stripos(uConfig::$dbdsn, "sqlite") === 0;
-      if (!$isSqlite && empty(uConfig::$dbuser)) {
+      $isSqlite = stripos($configDSN, "sqlite") === 0;
+      if (!$isSqlite && empty($configUser)) {
         $messages[] = sprintf($langSetup["nodbsettings"], "\$dbuser, \$dbpass");
       } else {
         $messages[] = $langSetup["dbconnectfailed"];
@@ -148,15 +178,15 @@ switch ($command) {
         $messages[] = sprintf($langSetup["serversaid"], "<b>" . htmlentities($e->getMessage()) . "</b>");
       }
       $messages[] = $langSetup["dorestart"];
-      $messages[] = "<form method=\"post\" action=\"setup.php\"><button>{$langSetup["restartbutton"]}</button></form>";
+      $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><button>{$langSetup["restartbutton"]}</button></form>";
       break;
     }
     $pdo = null;
-    $dbName = uDb::getDbName(uConfig::$dbdsn);
+    $dbName = uDb::getDbName($configDSN);
     $dbName = empty($dbName) ? '""' : "<b>" . htmlentities($dbName) . "</b>";
     $messages[] = sprintf($langSetup["scriptdesc"], "'$tPositions', '$tTracks', '$tUsers'", $dbName);
     $messages[] = $langSetup["scriptdesc2"];
-    $messages[] = "<form method=\"post\" action=\"setup.php\"><input type=\"hidden\" name=\"command\" value=\"setup\"><button>{$langSetup["startbutton"]}</button></form>";
+    $messages[] = "<form method=\"post\" action=\"setup.php?lang=$language\"><input type=\"hidden\" name=\"command\" value=\"setup\"><button>{$langSetup["startbutton"]}</button></form>";
     break;
 }
 
@@ -417,14 +447,15 @@ function getQueries($dbDriver) {
  * @throws PDOException
  */
 function getPdo() {
-  $options = [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION];
-  return new PDO(uConfig::$dbdsn, uConfig::$dbuser, uConfig::$dbpass, $options);
+  global $configDSN, $configUser, $configPass;
+  $options = [ PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION ];
+  return new PDO($configDSN, $configUser, $configPass, $options);
 }
 
 ?>
 
 <!DOCTYPE html>
-<html lang="<?= uConfig::$lang ?>">
+<html lang="<?= $language ?>">
 <head>
   <title><?= $lang["title"] ?></title>
   <meta http-equiv="Content-type" content="text/html;charset=UTF-8">
@@ -455,6 +486,14 @@ function getPdo() {
       -webkit-border-radius: 5px;
     }
 
+    #language {
+      text-align: right;
+    }
+
+    #language label {
+      font-size: small;
+    }
+
     .warn {
       color: #ffc747;
     }
@@ -466,7 +505,6 @@ function getPdo() {
   <!--suppress ES6ConvertVarToLetConst -->
   <script>
     var lang = <?= json_encode($lang) ?>;
-    var pass_regex = <?= uConfig::passRegex() ?>;
 
     function validateForm() {
       var form = document.getElementById('userForm');
@@ -481,12 +519,13 @@ function getPdo() {
         alert(lang['passnotmatch']);
         return false;
       }
-      if (!pass_regex.test(pass)) {
-        alert(lang['passlenmin'] + '\n' + lang['passrules']);
-        return false;
-      }
       return true;
     }
+
+    function changeLang(el) {
+      window.location = '?lang=' + el.value;
+      return false;
+    }
   </script>
 </head>
 
diff --git a/utils/changepass.php b/utils/changepass.php
index b7c29f4..4452cad 100644
--- a/utils/changepass.php
+++ b/utils/changepass.php
@@ -17,44 +17,49 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  require_once(dirname(__DIR__) . "/helpers/auth.php");
-  require_once(ROOT_DIR . "/helpers/utils.php");
+require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/config.php");
+require_once(ROOT_DIR . "/helpers/utils.php");
 
-  $auth = new uAuth();
-  if (!$auth->isAuthenticated()) {
-    $auth->sendUnauthorizedHeader();
-    uUtils::exitWithError("Unauthorized");
-  }
+$auth = new uAuth();
+$config = uConfig::getInstance();
+if (!$auth->isAuthenticated()) {
+  $auth->sendUnauthorizedHeader();
+  uUtils::exitWithError("Unauthorized");
+}
 
-  $login = uUtils::postString('login');
-  $oldpass = uUtils::postPass('oldpass');
-  $pass = uUtils::postPass('pass');
-  // FIXME: strings need to be localized
-  if (empty($pass)) {
-    uUtils::exitWithError("Empty password");
+$login = uUtils::postString('login');
+$oldpass = uUtils::postPass('oldpass');
+$pass = uUtils::postPass('pass');
+// FIXME: strings need to be localized
+if (empty($pass)) {
+  uUtils::exitWithError("Empty password");
+}
+if (!$config->validPassStrength($pass)) {
+  uUtils::exitWithError("Invalid password strength");
+}
+if (empty($login)) {
+  uUtils::exitWithError("Empty login");
+}
+if ($auth->user->login === $login) {
+  // current user
+  $passUser = $auth->user;
+  if (!$passUser->validPassword($oldpass)) {
+    uUtils::exitWithError("Wrong old password");
   }
-  if (empty($login)) {
-    uUtils::exitWithError("Empty login");
+} else if ($auth->isAdmin()) {
+  // different user, only admin
+  $passUser = new uUser($login);
+  if (!$passUser->isValid) {
+    uUtils::exitWithError("User unknown");
   }
-  if ($auth->user->login === $login) {
-    // current user
-    $passUser = $auth->user;
-    if (!$passUser->validPassword($oldpass)) {
-      uUtils::exitWithError("Wrong old password");
-    }
-  } else if ($auth->isAdmin()) {
-    // different user, only admin
-    $passUser = new uUser($login);
-    if (!$passUser->isValid) {
-      uUtils::exitWithError("User unknown");
-    }
-  } else {
-    uUtils::exitWithError("Unauthorized");
-  }
-  if ($passUser->setPass($pass) === false) {
-    uUtils::exitWithError("Server error");
-  }
-  $auth->updateSession();
-  uUtils::exitWithSuccess();
+} else {
+  uUtils::exitWithError("Unauthorized");
+}
+if ($passUser->setPass($pass) === false) {
+  uUtils::exitWithError("Server error");
+}
+$auth->updateSession();
+uUtils::exitWithSuccess();
 
 ?>
\ No newline at end of file
diff --git a/utils/export.php b/utils/export.php
index 9e78fb8..3c6a3b8 100644
--- a/utils/export.php
+++ b/utils/export.php
@@ -23,7 +23,8 @@ require_once(ROOT_DIR . "/helpers/lang.php");
 require_once(ROOT_DIR . "/helpers/config.php");
 
 $auth = new uAuth();
-$lang = (new uLang(uConfig::$lang))->getStrings();
+$config = uConfig::getInstance();
+$lang = (new uLang($config))->getStrings();
 
 /**
  * Add kml marker style element
@@ -62,13 +63,13 @@ $type = uUtils::getString('type', 'kml');
 $userId = uUtils::getInt('userid');
 $trackId = uUtils::getInt('trackid');
 
-if (!uConfig::$publicTracks &&
+if (!$config->publicTracks &&
     (!$auth->isAuthenticated() || (!$auth->isAdmin() && $auth->user->id !== $userId))) {
   // unauthorized
   exit();
 }
 
-if (uConfig::$units === "imperial") {
+if ($config->units === "imperial") {
   $factor_kmh = 0.62; //to mph
   $unit_kmh = "mph";
   $factor_m = 3.28; // to feet
@@ -185,7 +186,7 @@ if ($trackId && $userId) {
       $xml->writeAttributeNs("xsi", "schemaLocation", NULL, "http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd https://github.com/bfabiszewski/ulogger-android/1 https://raw.githubusercontent.com/bfabiszewski/ulogger-server/master/scripts/gpx_extensions1.xsd");
       $xml->writeAttributeNs("xmlns", "xsi", NULL, "http://www.w3.org/2001/XMLSchema-instance");
       $xml->writeAttributeNs("xmlns", "ulogger", NULL, "https://github.com/bfabiszewski/ulogger-android/1");
-      $xml->writeAttribute("creator", "μlogger-server " . uConfig::$version);
+      $xml->writeAttribute("creator", "μlogger-server " . $config->version);
       $xml->writeAttribute("version", "1.1");
       $xml->startElement("metadata");
         $xml->writeElement("name", $positionsArr[0]->trackName);
diff --git a/utils/getinit.php b/utils/getinit.php
index 7f81cbe..edc1e2d 100644
--- a/utils/getinit.php
+++ b/utils/getinit.php
@@ -22,7 +22,8 @@ require_once(ROOT_DIR . "/helpers/config.php");
 require_once(ROOT_DIR . "/helpers/lang.php");
 
 $auth = new uAuth();
-$langStrings = (new uLang(uConfig::$lang))->getStrings();
+$config = uConfig::getInstance();
+$langStrings = (new uLang($config))->getStrings();
 
 $result = [];
 $resultAuth = [
@@ -35,20 +36,20 @@ if ($auth->isAuthenticated()) {
 }
 
 $resultConfig = [
-  "interval" => uConfig::$interval,
-  "units" => uConfig::$units,
-  "lang" => uConfig::$lang,
-  "mapApi" => uConfig::$mapApi,
-  "gkey" => uConfig::$googleKey,
-  "initLatitude" => uConfig::$initLatitude,
-  "initLongitude" => uConfig::$initLongitude,
-  "passRegex" => uConfig::passRegex(),
-  "strokeWeight" => uConfig::$strokeWeight,
-  "strokeColor" => uConfig::$strokeColor,
-  "strokeOpacity" => uConfig::$strokeOpacity,
+  "interval" => $config->interval,
+  "units" => $config->units,
+  "lang" => $config->lang,
+  "mapApi" => $config->mapApi,
+  "gkey" => $config->googleKey,
+  "initLatitude" => $config->initLatitude,
+  "initLongitude" => $config->initLongitude,
+  "passRegex" => $config->passRegex(),
+  "strokeWeight" => $config->strokeWeight,
+  "strokeColor" => $config->strokeColor,
+  "strokeOpacity" => $config->strokeOpacity,
   "olLayers" => []
 ];
-foreach (uConfig::$olLayers as $key => $val) {
+foreach ($config->olLayers as $key => $val) {
   $resultConfig["olLayers"][$key] = $val;
 }
 
diff --git a/utils/getpositions.php b/utils/getpositions.php
index e9d256a..cb80a18 100644
--- a/utils/getpositions.php
+++ b/utils/getpositions.php
@@ -18,10 +18,12 @@
  */
 
 require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/config.php");
 require_once(ROOT_DIR . "/helpers/position.php");
 require_once(ROOT_DIR . "/helpers/utils.php");
 
 $auth = new uAuth();
+$config = uConfig::getInstance();
 
 $userId = uUtils::getInt('userid');
 $trackId = uUtils::getInt('trackid');
@@ -30,7 +32,7 @@ $last = uUtils::getBool('last');
 
 $positionsArr = [];
 if ($userId) {
-  if (uConfig::$publicTracks ||
+  if ($config->publicTracks ||
       ($auth->isAuthenticated() && ($auth->isAdmin() || $auth->user->id === $userId))) {
     if ($trackId) {
       // get all track data
@@ -44,7 +46,7 @@ if ($userId) {
     }
   }
 } else if ($last) {
-  if (uConfig::$publicTracks || ($auth->isAuthenticated() && ($auth->isAdmin()))) {
+  if ($config->publicTracks || ($auth->isAuthenticated() && ($auth->isAdmin()))) {
     $positionsArr = uPosition::getLastAllUsers();
   }
 }
diff --git a/utils/gettracks.php b/utils/gettracks.php
index a197ade..4a7e8e2 100644
--- a/utils/gettracks.php
+++ b/utils/gettracks.php
@@ -18,15 +18,17 @@
  */
 
 require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/config.php");
 require_once(ROOT_DIR . "/helpers/track.php");
 
 $auth = new uAuth();
+$config = uConfig::getInstance();
 
 $userId = uUtils::getInt('userid');
 
 $tracksArr = [];
 if ($userId) {
-  if (uConfig::$publicTracks ||
+  if ($config->publicTracks ||
       ($auth->isAuthenticated() && ($auth->isAdmin() || $auth->user->id === $userId))) {
     $tracksArr = uTrack::getAll($userId);
   }
diff --git a/utils/getusers.php b/utils/getusers.php
index 25bcc96..2dc671f 100644
--- a/utils/getusers.php
+++ b/utils/getusers.php
@@ -19,12 +19,14 @@
  */
 
 require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/config.php");
 require_once(ROOT_DIR . "/helpers/track.php");
 
 $auth = new uAuth();
+$config = uConfig::getInstance();
 
 $usersArr = [];
-if (uConfig::$publicTracks || $auth->isAdmin()) {
+if ($config->publicTracks || $auth->isAdmin()) {
   $usersArr = uUser::getAll();
 } else if ($auth->isAuthenticated()) {
   $usersArr = [ $auth->user ];
diff --git a/utils/handleposition.php b/utils/handleposition.php
index 19bbdae..69dd43e 100644
--- a/utils/handleposition.php
+++ b/utils/handleposition.php
@@ -17,49 +17,50 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  require_once(dirname(__DIR__) . "/helpers/auth.php");
-  require_once(ROOT_DIR . "/helpers/lang.php");
-  require_once(ROOT_DIR . "/helpers/track.php");
-  require_once(ROOT_DIR . "/helpers/utils.php");
-  require_once(ROOT_DIR . "/helpers/config.php");
+require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/lang.php");
+require_once(ROOT_DIR . "/helpers/track.php");
+require_once(ROOT_DIR . "/helpers/utils.php");
+require_once(ROOT_DIR . "/helpers/config.php");
 
-  $auth = new uAuth();
+$auth = new uAuth();
 
-  $action = uUtils::postString('action');
-  $positionId = uUtils::postInt('posid');
-  $comment = uUtils::postString('comment');
+$action = uUtils::postString('action');
+$positionId = uUtils::postInt('posid');
+$comment = uUtils::postString('comment');
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+$config = uConfig::getInstance();
+$lang = (new uLang($config))->getStrings();
 
-  if (empty($action) || empty($positionId)) {
-    uUtils::exitWithError($lang["servererror"]);
-  }
-  $position = new uPosition($positionId);
-  if (!$position->isValid ||
-      (!$auth->isAuthenticated() || (!$auth->isAdmin() && $auth->user->id !== $position->userId))) {
-    uUtils::exitWithError($lang["servererror"]);
-  }
+if (empty($action) || empty($positionId)) {
+  uUtils::exitWithError($lang["servererror"]);
+}
+$position = new uPosition($positionId);
+if (!$position->isValid ||
+  (!$auth->isAuthenticated() || (!$auth->isAdmin() && $auth->user->id !== $position->userId))) {
+  uUtils::exitWithError($lang["servererror"]);
+}
 
-  switch ($action) {
+switch ($action) {
 
-    case 'update':
-      $position->comment = $comment;
-      if ($position->update() === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    case 'delete':
-      if ($position->delete() === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    default:
+  case 'update':
+    $position->comment = $comment;
+    if ($position->update() === false) {
       uUtils::exitWithError($lang["servererror"]);
-      break;
-  }
+    }
+    break;
 
-  uUtils::exitWithSuccess();
+  case 'delete':
+    if ($position->delete() === false) {
+      uUtils::exitWithError($lang["servererror"]);
+    }
+    break;
+
+  default:
+    uUtils::exitWithError($lang["servererror"]);
+    break;
+}
+
+uUtils::exitWithSuccess();
 
 ?>
\ No newline at end of file
diff --git a/utils/handletrack.php b/utils/handletrack.php
index 908529b..b92c764 100644
--- a/utils/handletrack.php
+++ b/utils/handletrack.php
@@ -17,48 +17,49 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  require_once(dirname(__DIR__) . "/helpers/auth.php");
-  require_once(ROOT_DIR . "/helpers/lang.php");
-  require_once(ROOT_DIR . "/helpers/track.php");
-  require_once(ROOT_DIR . "/helpers/utils.php");
-  require_once(ROOT_DIR . "/helpers/config.php");
+require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/lang.php");
+require_once(ROOT_DIR . "/helpers/track.php");
+require_once(ROOT_DIR . "/helpers/utils.php");
+require_once(ROOT_DIR . "/helpers/config.php");
 
-  $auth = new uAuth();
+$auth = new uAuth();
 
-  $action = uUtils::postString('action');
-  $trackId = uUtils::postInt('trackid');
-  $trackName = uUtils::postString('trackname');
+$action = uUtils::postString('action');
+$trackId = uUtils::postInt('trackid');
+$trackName = uUtils::postString('trackname');
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+$config = uConfig::getInstance();
+$lang = (new uLang($config))->getStrings();
 
-  if (empty($action) || empty($trackId)) {
-    uUtils::exitWithError($lang["servererror"]);
-  }
-  $track = new uTrack($trackId);
-  if (!$track->isValid ||
-      (!$auth->isAuthenticated() || (!$auth->isAdmin() && $auth->user->id !== $track->userId))) {
-    uUtils::exitWithError($lang["servererror"]);
-  }
+if (empty($action) || empty($trackId)) {
+  uUtils::exitWithError($lang["servererror"]);
+}
+$track = new uTrack($trackId);
+if (!$track->isValid ||
+  (!$auth->isAuthenticated() || (!$auth->isAdmin() && $auth->user->id !== $track->userId))) {
+  uUtils::exitWithError($lang["servererror"]);
+}
 
-  switch ($action) {
+switch ($action) {
 
-    case 'update':
-      if (empty($trackName) || $track->update($trackName) === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    case 'delete':
-      if ($track->delete() === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    default:
+  case 'update':
+    if (empty($trackName) || $track->update($trackName) === false) {
       uUtils::exitWithError($lang["servererror"]);
-      break;
-  }
+    }
+    break;
 
-  uUtils::exitWithSuccess();
+  case 'delete':
+    if ($track->delete() === false) {
+      uUtils::exitWithError($lang["servererror"]);
+    }
+    break;
+
+  default:
+    uUtils::exitWithError($lang["servererror"]);
+    break;
+}
+
+uUtils::exitWithSuccess();
 
 ?>
\ No newline at end of file
diff --git a/utils/handleuser.php b/utils/handleuser.php
index 4cd8720..b6fd871 100644
--- a/utils/handleuser.php
+++ b/utils/handleuser.php
@@ -17,63 +17,64 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-  require_once(dirname(__DIR__) . "/helpers/auth.php");
-  require_once(ROOT_DIR . "/helpers/lang.php");
-  require_once(ROOT_DIR . "/helpers/config.php");
-  require_once(ROOT_DIR . "/helpers/utils.php");
+require_once(dirname(__DIR__) . "/helpers/auth.php");
+require_once(ROOT_DIR . "/helpers/lang.php");
+require_once(ROOT_DIR . "/helpers/config.php");
+require_once(ROOT_DIR . "/helpers/utils.php");
 
-  $auth = new uAuth();
+$auth = new uAuth();
+$config = uConfig::getInstance();
 
-  $action = uUtils::postString('action');
-  $login = uUtils::postString('login');
-  $pass = uUtils::postPass('pass');
-  $admin = uUtils::postBool('admin', false);
+$action = uUtils::postString('action');
+$login = uUtils::postString('login');
+$pass = uUtils::postPass('pass');
+$admin = uUtils::postBool('admin', false);
 
-  $lang = (new uLang(uConfig::$lang))->getStrings();
+$lang = (new uLang($config))->getStrings();
 
-  if (!$auth->isAuthenticated() || !$auth->isAdmin() || $auth->user->login === $login || empty($action) || empty($login)) {
-    uUtils::exitWithError($lang["servererror"]);
-  }
+if ($auth->user->login === $login || empty($action) || empty($login) || !$auth->isAuthenticated() || !$auth->isAdmin()) {
+  uUtils::exitWithError($lang["servererror"]);
+}
 
-  if ($admin && !$auth->isAdmin()) {
-    uUtils::exitWithError($lang["notauthorized"]);
-  }
+if ($admin && !$auth->isAdmin()) {
+  uUtils::exitWithError($lang["notauthorized"]);
+}
 
-  $aUser = new uUser($login);
-  $data = NULL;
+$aUser = new uUser($login);
+$data = NULL;
 
-  switch ($action) {
-    case 'add':
-      if ($aUser->isValid) {
-        uUtils::exitWithError($lang["userexists"]);
-      }
-      if (empty($pass) || ($userId = uUser::add($login, $pass, $admin)) === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      } else {
-        $data = [ 'id' => $userId ];
-      }
-      break;
-
-    case 'update':
-      if ($aUser->setAdmin($admin) === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      if (!empty($pass) && $aUser->setPass($pass) === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    case 'delete':
-      if ($aUser->delete() === false) {
-        uUtils::exitWithError($lang["servererror"]);
-      }
-      break;
-
-    default:
+switch ($action) {
+  case 'add':
+    if ($aUser->isValid) {
+      uUtils::exitWithError($lang["userexists"]);
+    }
+    if (empty($pass) || !$config->validPassStrength($pass) || ($userId = uUser::add($login, $pass, $admin)) === false) {
       uUtils::exitWithError($lang["servererror"]);
-      break;
-  }
+    } else {
+      $data = [ 'id' => $userId ];
+    }
+    break;
 
-  uUtils::exitWithSuccess($data);
+  case 'update':
+    if ($aUser->setAdmin($admin) === false) {
+      uUtils::exitWithError($lang["servererror"]);
+    }
+    if (!empty($pass) && (!$config->validPassStrength($pass) || $aUser->setPass($pass) === false)) {
+      uUtils::exitWithError($lang["servererror"]);
+    }
+    break;
+
+  case 'delete':
+    if ($aUser->delete() === false) {
+      uUtils::exitWithError($lang["servererror"]);
+    }
+    break;
+
+  default:
+    uUtils::exitWithError($lang["servererror"]);
+    break;
+}
+
+uUtils::exitWithSuccess($data);
 
 ?>
\ No newline at end of file
diff --git a/utils/import.php b/utils/import.php
index 737f999..8dffe8c 100644
--- a/utils/import.php
+++ b/utils/import.php
@@ -26,7 +26,8 @@ require_once(ROOT_DIR . "/helpers/lang.php");
 
 $auth = new uAuth();
 
-$lang = (new uLang(uConfig::$lang))->getStrings();
+$config = uConfig::getInstance();
+$lang = (new uLang($config))->getStrings();
 
 $uploadErrors = [];
 $uploadErrors[UPLOAD_ERR_INI_SIZE] = "The uploaded file exceeds the upload_max_filesize directive in php.ini";