diff --git a/bin/icingacli b/bin/icingacli
index 1a0781222b..3f3cc47f17 100755
--- a/bin/icingacli
+++ b/bin/icingacli
@@ -1,6 +1,17 @@
 #!/usr/bin/php
+
 <?php
+// {{{ICINGA_LICENSE_HEADER}}}
+// {{{ICINGA_LICENSE_HEADER}}}
+
+define('ICINGAWEB_BASEDIR', dirname(__DIR__));
+// ICINGAWEB_BASEDIR is the parent folder for at least application, bin, modules, library/vendor and public
+
+
+if (! @include_once ICINGAWEB_BASEDIR . '/library/Icinga/Application/Cli.php') {
+    // If the Icinga library wasn't found under ICINGAWEB_BASEDIR, require that the Icinga library is found in PHP's
+    // include path which is the case if Icinga Web 2 is installed via packages
+    require_once 'Icinga/Application/Cli.php';
+}
 
-use Icinga\Application\Cli;
-require_once dirname(__DIR__) . '/library/Icinga/Application/Cli.php';
-Cli::start()->dispatch();
+Icinga\Application\Cli::start()->dispatch();
diff --git a/library/Icinga/Application/ApplicationBootstrap.php b/library/Icinga/Application/ApplicationBootstrap.php
index f7b2b0c90d..ebd5641635 100644
--- a/library/Icinga/Application/ApplicationBootstrap.php
+++ b/library/Icinga/Application/ApplicationBootstrap.php
@@ -6,6 +6,7 @@
 
 use ErrorException;
 use Exception;
+use LogicException;
 use Icinga\Application\Modules\Manager as ModuleManager;
 use Icinga\Data\ResourceFactory;
 use Icinga\Exception\ConfigurationError;
@@ -101,23 +102,14 @@ abstract class ApplicationBootstrap
      */
     protected function __construct($configDir = null)
     {
-        $this->libDir = realpath(__DIR__ . '/../..');
-
-        if (!defined('ICINGA_LIBDIR')) {
-            define('ICINGA_LIBDIR', $this->libDir);
-        }
-
-        if (defined('ICINGAWEB_APPDIR')) {
-            $this->appDir = ICINGAWEB_APPDIR;
-        } elseif (array_key_exists('ICINGAWEB_APPDIR', $_SERVER)) {
-            $this->appDir = $_SERVER['ICINGAWEB_APPDIR'];
-        } else {
-            $this->appDir = realpath($this->libDir. '/../application');
+        if (! defined('ICINGAWEB_BASEDIR')) {
+            define('ICINGAWEB_BASEDIR', dirname($this->getBootstrapDirecory()));
         }
+        define('ICINGAWEB_VENDORS', ICINGAWEB_BASEDIR . '/library/vendor');
+        define('ICINGAWEB_APPDIR', ICINGAWEB_BASEDIR . '/application');
 
-        if (!defined('ICINGAWEB_APPDIR')) {
-            define('ICINGAWEB_APPDIR', $this->appDir);
-        }
+        $this->appDir = ICINGAWEB_APPDIR;
+        $this->libDir = realpath(__DIR__ . '/../..');
 
         if ($configDir === null) {
             if (array_key_exists('ICINGAWEB_CONFIGDIR', $_SERVER)) {
@@ -416,7 +408,7 @@ protected function setupErrorHandling()
      */
     protected function setupLogger()
     {
-        if (($loggingConfig = $this->config->get('logging')) !== null) {
+        if (($loggingConfig = $this->config->logging) !== null) {
             try {
                 Logger::create($loggingConfig);
             } catch (ConfigurationError $e) {
diff --git a/library/Icinga/Data/Filter/Filter.php b/library/Icinga/Data/Filter/Filter.php
index 64607a4a0c..99b0290f15 100644
--- a/library/Icinga/Data/Filter/Filter.php
+++ b/library/Icinga/Data/Filter/Filter.php
@@ -79,7 +79,7 @@ public function applyChanges($changes)
             }
         }
 
-        krsort($operators, SORT_NATURAL);
+        krsort($operators, version_compare(PHP_VERSION, '5.4.0') >= 0 ? SORT_NATURAL : SORT_REGULAR);
         foreach ($operators as $id => $operator) {
             $f = $filter->getById($id);
             if ($f->getOperatorName() !== $operator) {
diff --git a/library/Icinga/Web/Widget/Tab.php b/library/Icinga/Web/Widget/Tab.php
index 92a1a99543..28c04e6abe 100644
--- a/library/Icinga/Web/Widget/Tab.php
+++ b/library/Icinga/Web/Widget/Tab.php
@@ -201,7 +201,7 @@ public function render()
         $caption = $view->escape($this->title);
 
         if ($this->icon !== null) {
-            $caption = $view->img($this->icon, array('class' => 'icon')) . ' ' . $caption;
+            $caption = $view->img($this->icon, array('class' => 'icon')) . $caption;
         }
         if ($this->url !== null) {
             $this->url->overwriteParams($this->urlParams);
diff --git a/public/index.php b/public/index.php
index 1715811553..085f737473 100644
--- a/public/index.php
+++ b/public/index.php
@@ -2,4 +2,8 @@
 // {{{ICINGA_LICENSE_HEADER}}}
 // {{{ICINGA_LICENSE_HEADER}}}
 
-require_once dirname(__DIR__). '/library/Icinga/Application/webrouter.php';
+if (! @include_once dirname(__DIR__) . '/library/Icinga/Application/webrouter.php') {
+    // If the Icinga library wasn't found under ICINGAWEB_BASEDIR, require that the Icinga library is found in PHP's
+    // include path which is the case if Icinga Web 2 is installed via packages
+    require_once 'Icinga/Application/webrouter.php';
+}