diff --git a/include/dba.php b/include/dba.php
index d2f631c06..1d3b43214 100644
--- a/include/dba.php
+++ b/include/dba.php
@@ -1,5 +1,6 @@
 <?php
 
+use Friendica\App;
 use Friendica\Core\L10n;
 use Friendica\Core\System;
 use Friendica\Database\DBM;
@@ -24,7 +25,7 @@ class dba {
 	private static $in_transaction = false;
 	private static $relation = [];
 
-	public static function connect($serveraddr, $user, $pass, $db, $install = false) {
+	public static function connect($serveraddr, $user, $pass, $db) {
 		if (!is_null(self::$db)) {
 			return true;
 		}
@@ -51,7 +52,7 @@ class dba {
 			return false;
 		}
 
-		if ($install) {
+		if ($a->mode == App::MODE_INSTALL) {
 			// server has to be a non-empty string that is not 'localhost' and not an IP
 			if (strlen($server) && ($server !== 'localhost') && filter_var($server, FILTER_VALIDATE_IP) === false) {
 				if (! dns_get_record($server, DNS_A + DNS_CNAME)) {
@@ -93,6 +94,7 @@ class dba {
 
 		// No suitable SQL driver was found.
 		if (!self::$connected) {
+			self::$driver = null;
 			self::$db = null;
 		}
 		$a->save_timestamp($stamp1, "network");
diff --git a/include/text.php b/include/text.php
index 0542c459a..4c9a8864d 100644
--- a/include/text.php
+++ b/include/text.php
@@ -637,7 +637,7 @@ function logger($msg, $level = 0) {
 
 	// turn off logger in install mode
 	if (
-		$a->module == 'install'
+		$a->mode == App::MODE_INSTALL
 		|| !dba::$connected
 	) {
 		return;
@@ -709,7 +709,7 @@ function dlogger($msg, $level = 0) {
 
 	// turn off logger in install mode
 	if (
-		$a->module == 'install'
+		$a->mode == App::MODE_INSTALL
 		|| !dba::$connected
 	) {
 		return;
diff --git a/index.php b/index.php
index b7ae6f1d4..aeda99982 100644
--- a/index.php
+++ b/index.php
@@ -31,16 +31,8 @@ BaseObject::setApp($a);
 // The value is set to "true" by default in boot.php
 $a->backend = false;
 
-/**
- * Load the configuration file which contains our DB credentials.
- * Ignore errors. If the file doesn't exist or is empty, we are running in
- * installation mode.
- */
-
-$install = ((file_exists('.htconfig.php') && filesize('.htconfig.php')) ? false : true);
-
-// Only load config if found, don't surpress errors
-if (!$install) {
+// Only load config if found, don't suppress errors
+if (!$a->mode == App::MODE_INSTALL) {
 	include ".htconfig.php";
 }
 
@@ -50,7 +42,7 @@ if (!$install) {
 
 require_once "include/dba.php";
 
-if (!$install) {
+if (!$a->mode == App::MODE_INSTALL) {
 	$result = dba::connect($db_host, $db_user, $db_pass, $db_data);
 	unset($db_host, $db_user, $db_pass, $db_data);
 
@@ -85,7 +77,7 @@ if (!$install) {
 	Addon::loadHooks();
 	Addon::callHooks('init_1');
 
-	$maintenance = Config::get('system', 'maintenance');
+	$a->checkMaintenanceMode();
 }
 
 $lang = L10n::getBrowserLanguage();
@@ -129,7 +121,7 @@ if ((x($_SESSION, 'language')) && ($_SESSION['language'] !== $lang)) {
 	L10n::loadTranslationTable($lang);
 }
 
-if ((x($_GET, 'zrl')) && (!$install && !$maintenance)) {
+if ((x($_GET, 'zrl')) && $a->mode == App::MODE_NORMAL) {
 	// Only continue when the given profile link seems valid
 	// Valid profile links contain a path with "/profile/" and no query parameters
 	if ((parse_url($_GET['zrl'], PHP_URL_QUERY) == "")
@@ -181,9 +173,9 @@ $_SESSION['last_updated'] = defaults($_SESSION, 'last_updated', []);
 
 // in install mode, any url loads install module
 // but we need "view" module for stylesheet
-if ($install && $a->module!="view") {
+if ($a->mode == App::MODE_INSTALL && $a->module!="view") {
 	$a->module = 'install';
-} elseif ($maintenance && $a->module!="view") {
+} elseif ($a->mode == App::MODE_MAINTENANCE && $a->module!="view") {
 	$a->module = 'maintenance';
 } else {
 	check_url($a);
@@ -342,7 +334,7 @@ if (! x($a->page, 'content')) {
 	$a->page['content'] = '';
 }
 
-if (!$install && !$maintenance) {
+if ($a->mode == App::MODE_NORMAL) {
 	Addon::callHooks('page_content_top', $a->page['content']);
 }
 
diff --git a/mod/install.php b/mod/install.php
index 06f728729..4596f9a25 100644
--- a/mod/install.php
+++ b/mod/install.php
@@ -5,11 +5,9 @@
 
 use Friendica\App;
 use Friendica\Core\L10n;
+use Friendica\Core\Install;
 use Friendica\Core\System;
 use Friendica\Database\DBM;
-use Friendica\Database\DBStructure;
-use Friendica\Object\Image;
-use Friendica\Util\Network;
 use Friendica\Util\Temporal;
 
 $install_wizard_pass = 1;
@@ -27,6 +25,8 @@ function install_init(App $a) {
 	$a->config['system']['theme'] = "../install";
 	$a->theme['stylesheet'] = System::baseUrl()."/view/install/style.css";
 
+	Install::setInstallMode();
+
 	global $install_wizard_pass;
 	if (x($_POST, 'pass')) {
 		$install_wizard_pass = intval($_POST['pass']);
@@ -51,7 +51,7 @@ function install_post(App $a) {
 			$phpath = notags(trim($_POST['phpath']));
 
 			require_once("include/dba.php");
-			if (!dba::connect($dbhost, $dbuser, $dbpass, $dbdata, true)) {
+			if (!dba::connect($dbhost, $dbuser, $dbpass, $dbdata)) {
 				$a->data['db_conn_failed'] = true;
 			}
 
@@ -70,36 +70,9 @@ function install_post(App $a) {
 			$rino = 1;
 
 			// connect to db
-			dba::connect($dbhost, $dbuser, $dbpass, $dbdata, true);
+			dba::connect($dbhost, $dbuser, $dbpass, $dbdata);
 
-			$tpl = get_markup_template('htconfig.tpl');
-			$txt = replace_macros($tpl,[
-				'$dbhost' => $dbhost,
-				'$dbuser' => $dbuser,
-				'$dbpass' => $dbpass,
-				'$dbdata' => $dbdata,
-				'$timezone' => $timezone,
-				'$language' => $language,
-				'$urlpath' => $urlpath,
-				'$phpath' => $phpath,
-				'$adminmail' => $adminmail,
-				'$rino' => $rino
-			]);
-
-
-			$result = file_put_contents('.htconfig.php', $txt);
-			if (! $result) {
-				$a->data['txt'] = $txt;
-			}
-
-			$errors = load_database();
-
-
-			if ($errors) {
-				$a->data['db_failed'] = $errors;
-			} else {
-				$a->data['db_installed'] = true;
-			}
+			Install::install($urlpath, $dbhost, $dbuser, $dbpass, $dbdata, $phpath, $timezone, $language, $adminmail, $rino);
 
 			return;
 		break;
@@ -167,37 +140,11 @@ function install_content(App $a) {
 	switch ($install_wizard_pass) {
 		case 1: { // System check
 
-
-			$checks = [];
-
-			check_funcs($checks);
-
-			check_imagik($checks);
-
-			check_htconfig($checks);
-
-			check_smarty3($checks);
-
-			check_keys($checks);
-
 			if (x($_POST, 'phpath')) {
 				$phpath = notags(trim($_POST['phpath']));
 			}
 
-			check_php($phpath, $checks);
-
-			check_htaccess($checks);
-
-			/// @TODO Maybe move this out?
-			function check_passed($v, $c) {
-				if ($c['required']) {
-					$v = $v && $c['status'];
-				}
-				return $v;
-			}
-			$checkspassed = array_reduce($checks, "check_passed", true);
-
-
+			list($checks, $checkspassed) = Install::check($phpath);
 
 			$tpl = get_markup_template('install_checks.tpl');
 			$o .= replace_macros($tpl, [
@@ -296,245 +243,6 @@ function install_content(App $a) {
 	}
 }
 
-/**
- * checks   : array passed to template
- * title    : string
- * status   : boolean
- * required : boolean
- * help		: string optional
- */
-function check_add(&$checks, $title, $status, $required, $help, $error_msg = "") {
-	$checks[] = [
-		'title' => $title,
-		'status' => $status,
-		'required' => $required,
-		'help'	=> $help,
-		'error_msg' => $error_msg,
-	];
-}
-
-function check_php(&$phpath, &$checks) {
-	$passed = $passed2 = $passed3 = false;
-	if (strlen($phpath)) {
-		$passed = file_exists($phpath);
-	} else {
-		$phpath = trim(shell_exec('which php'));
-		$passed = strlen($phpath);
-	}
-	$help = "";
-	if (!$passed) {
-		$help .= L10n::t('Could not find a command line version of PHP in the web server PATH.'). EOL;
-		$help .= L10n::t("If you don't have a command line version of PHP installed on your server, you will not be able to run the background processing. See <a href='https://github.com/friendica/friendica/blob/master/doc/Install.md#set-up-the-worker'>'Setup the worker'</a>") . EOL;
-		$help .= EOL . EOL;
-		$tpl = get_markup_template('field_input.tpl');
-		$help .= replace_macros($tpl, [
-			'$field' => ['phpath', L10n::t('PHP executable path'), $phpath, L10n::t('Enter full path to php executable. You can leave this blank to continue the installation.')],
-		]);
-		$phpath = "";
-	}
-
-	check_add($checks, L10n::t('Command line PHP').($passed?" (<tt>$phpath</tt>)":""), $passed, false, $help);
-
-	if ($passed) {
-		$cmd = "$phpath -v";
-		$result = trim(shell_exec($cmd));
-		$passed2 = ( strpos($result, "(cli)") !== false);
-		list($result) = explode("\n", $result);
-		$help = "";
-		if (!$passed2) {
-			$help .= L10n::t("PHP executable is not the php cli binary \x28could be cgi-fgci version\x29"). EOL;
-			$help .= L10n::t('Found PHP version: ')."<tt>$result</tt>";
-		}
-		check_add($checks, L10n::t('PHP cli binary'), $passed2, true, $help);
-	}
-
-
-	if ($passed2) {
-		$str = autoname(8);
-		$cmd = "$phpath testargs.php $str";
-		$result = trim(shell_exec($cmd));
-		$passed3 = $result == $str;
-		$help = "";
-		if (!$passed3) {
-			$help .= L10n::t('The command line version of PHP on your system does not have "register_argc_argv" enabled.'). EOL;
-			$help .= L10n::t('This is required for message delivery to work.');
-		}
-		check_add($checks, L10n::t('PHP register_argc_argv'), $passed3, true, $help);
-	}
-
-
-}
-
-function check_keys(&$checks) {
-
-	$help = '';
-
-	$res = false;
-
-	if (function_exists('openssl_pkey_new')) {
-		$res = openssl_pkey_new([
-			'digest_alg'       => 'sha1',
-			'private_key_bits' => 4096,
-			'encrypt_key'      => false
-		]);
-	}
-
-	// Get private key
-
-	if (! $res) {
-		$help .= L10n::t('Error: the "openssl_pkey_new" function on this system is not able to generate encryption keys'). EOL;
-		$help .= L10n::t('If running under Windows, please see "http://www.php.net/manual/en/openssl.installation.php".');
-	}
-	check_add($checks, L10n::t('Generate encryption keys'), $res, true, $help);
-
-}
-
-
-function check_funcs(&$checks) {
-	$ck_funcs = [];
-	check_add($ck_funcs, L10n::t('libCurl PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('GD graphics PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('OpenSSL PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('PDO or MySQLi PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('mb_string PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('XML PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('iconv PHP module'), true, true, "");
-	check_add($ck_funcs, L10n::t('POSIX PHP module'), true, true, "");
-
-	if (function_exists('apache_get_modules')) {
-		if (! in_array('mod_rewrite',apache_get_modules())) {
-			check_add($ck_funcs, L10n::t('Apache mod_rewrite module'), false, true, L10n::t('Error: Apache webserver mod-rewrite module is required but not installed.'));
-		} else {
-			check_add($ck_funcs, L10n::t('Apache mod_rewrite module'), true, true, "");
-		}
-	}
-
-	if (! function_exists('curl_init')) {
-		$ck_funcs[0]['status'] = false;
-		$ck_funcs[0]['help'] = L10n::t('Error: libCURL PHP module required but not installed.');
-	}
-	if (! function_exists('imagecreatefromjpeg')) {
-		$ck_funcs[1]['status'] = false;
-		$ck_funcs[1]['help'] = L10n::t('Error: GD graphics PHP module with JPEG support required but not installed.');
-	}
-	if (! function_exists('openssl_public_encrypt')) {
-		$ck_funcs[2]['status'] = false;
-		$ck_funcs[2]['help'] = L10n::t('Error: openssl PHP module required but not installed.');
-	}
-	if (! function_exists('mysqli_connect') && !class_exists('pdo')) {
-		$ck_funcs[3]['status'] = false;
-		$ck_funcs[3]['help'] = L10n::t('Error: PDO or MySQLi PHP module required but not installed.');
-	}
-	if (!function_exists('mysqli_connect') && class_exists('pdo') && !in_array('mysql', PDO::getAvailableDrivers())) {
-		$ck_funcs[3]['status'] = false;
-		$ck_funcs[3]['help'] = L10n::t('Error: The MySQL driver for PDO is not installed.');
-	}
-	if (! function_exists('mb_strlen')) {
-		$ck_funcs[4]['status'] = false;
-		$ck_funcs[4]['help'] = L10n::t('Error: mb_string PHP module required but not installed.');
-	}
-	if (! function_exists('iconv_strlen')) {
-		$ck_funcs[6]['status'] = false;
-		$ck_funcs[6]['help'] = L10n::t('Error: iconv PHP module required but not installed.');
-	}
-	if (! function_exists('posix_kill')) {
-		$ck_funcs[7]['status'] = false;
-		$ck_funcs[7]['help'] = L10n::t('Error: POSIX PHP module required but not installed.');
-	}
-
-	$checks = array_merge($checks, $ck_funcs);
-
-	// check for XML DOM Documents being able to be generated
-	try {
-		$xml = new DOMDocument();
-	} catch (Exception $e) {
-		$ck_funcs[5]['status'] = false;
-		$ck_funcs[5]['help'] = L10n::t('Error, XML PHP module required but not installed.');
-	}
-}
-
-
-function check_htconfig(&$checks) {
-	$status = true;
-	$help = "";
-	if ((file_exists('.htconfig.php') && !is_writable('.htconfig.php')) ||
-		(!file_exists('.htconfig.php') && !is_writable('.'))) {
-
-		$status = false;
-		$help = L10n::t('The web installer needs to be able to create a file called ".htconfig.php" in the top folder of your web server and it is unable to do so.') .EOL;
-		$help .= L10n::t('This is most often a permission setting, as the web server may not be able to write files in your folder - even if you can.').EOL;
-		$help .= L10n::t('At the end of this procedure, we will give you a text to save in a file named .htconfig.php in your Friendica top folder.').EOL;
-		$help .= L10n::t('You can alternatively skip this procedure and perform a manual installation. Please see the file "INSTALL.txt" for instructions.').EOL;
-	}
-
-	check_add($checks, L10n::t('.htconfig.php is writable'), $status, false, $help);
-
-}
-
-function check_smarty3(&$checks) {
-	$status = true;
-	$help = "";
-	if (!is_writable('view/smarty3')) {
-
-		$status = false;
-		$help = L10n::t('Friendica uses the Smarty3 template engine to render its web views. Smarty3 compiles templates to PHP to speed up rendering.') .EOL;
-		$help .= L10n::t('In order to store these compiled templates, the web server needs to have write access to the directory view/smarty3/ under the Friendica top level folder.').EOL;
-		$help .= L10n::t("Please ensure that the user that your web server runs as \x28e.g. www-data\x29 has write access to this folder.").EOL;
-		$help .= L10n::t("Note: as a security measure, you should give the web server write access to view/smarty3/ only--not the template files \x28.tpl\x29 that it contains.").EOL;
-	}
-
-	check_add($checks, L10n::t('view/smarty3 is writable'), $status, true, $help);
-
-}
-
-function check_htaccess(&$checks) {
-	$status = true;
-	$help = "";
-	$error_msg = "";
-	if (function_exists('curl_init')) {
-		$test = Network::fetchUrlFull(System::baseUrl()."/install/testrewrite");
-
-		$url = normalise_link(System::baseUrl()."/install/testrewrite");
-		if ($test['body'] != "ok") {
-			$test = Network::fetchUrlFull($url);
-		}
-
-		if ($test['body'] != "ok") {
-			$status = false;
-			$help = L10n::t('Url rewrite in .htaccess is not working. Check your server configuration.');
-			$error_msg = [];
-			$error_msg['head'] = L10n::t('Error message from Curl when fetching');
-			$error_msg['url'] = $test['redirect_url'];
-			$error_msg['msg'] = $test['error'];
-		}
-		check_add($checks, L10n::t('Url rewrite is working'), $status, true, $help, $error_msg);
-	} else {
-		// cannot check modrewrite if libcurl is not installed
-		/// @TODO Maybe issue warning here?
-	}
-}
-
-function check_imagik(&$checks) {
-	$imagick = false;
-	$gif = false;
-
-	if (class_exists('Imagick')) {
-		$imagick = true;
-		$supported = Image::supportedTypes();
-		if (array_key_exists('image/gif', $supported)) {
-			$gif = true;
-		}
-	}
-	if ($imagick == false) {
-		check_add($checks, L10n::t('ImageMagick PHP extension is not installed'), $imagick, false, "");
-	} else {
-		check_add($checks, L10n::t('ImageMagick PHP extension is installed'), $imagick, false, "");
-		if ($imagick) {
-			check_add($checks, L10n::t('ImageMagick supports GIF'), $gif, false, "");
-		}
-	}
-}
-
 function manual_config(App $a) {
 	$data = htmlentities($a->data['txt'],ENT_COMPAT, 'UTF-8');
 	$o = L10n::t('The database configuration file ".htconfig.php" could not be written. Please use the enclosed text to create a configuration file in your web server root.');
@@ -551,12 +259,6 @@ function load_database_rem($v, $i) {
 	}
 }
 
-function load_database() {
-	$errors = DBStructure::update(false, true, true);
-
-	return $errors;
-}
-
 function what_next() {
 	$baseurl = System::baseUrl();
 	return
diff --git a/src/App.php b/src/App.php
index 815a02f28..f08f6f66d 100644
--- a/src/App.php
+++ b/src/App.php
@@ -32,6 +32,10 @@ require_once 'include/text.php';
  */
 class App
 {
+	const MODE_NORMAL = 0;
+	const MODE_INSTALL = 1;
+	const MODE_MAINTENANCE = 2;
+
 	public $module_loaded = false;
 	public $module_class = null;
 	public $query_string;
@@ -52,6 +56,7 @@ class App
 	public $argv;
 	public $argc;
 	public $module;
+	public $mode = App::MODE_NORMAL;
 	public $pager;
 	public $strings;
 	public $basepath;
@@ -288,6 +293,14 @@ class App
 		// Register template engines
 		$this->register_template_engine('Friendica\Render\FriendicaSmartyEngine');
 
+		/**
+		 * Load the configuration file which contains our DB credentials.
+		 * Ignore errors. If the file doesn't exist or is empty, we are running in
+		 * installation mode.	 *
+		 */
+		$this->mode = ((file_exists('.htconfig.php') && filesize('.htconfig.php')) ? App::MODE_NORMAL : App::MODE_INSTALL);
+
+
 		self::$a = $this;
 	}
 
@@ -1068,6 +1081,21 @@ class App
 		return $sender_email;
 	}
 
+	/**
+	 * @note Checks, if the App is in the Maintenance-Mode
+	 *
+	 * @return boolean
+	 */
+	public function checkMaintenanceMode()
+	{
+		if (Config::get('system', 'maintenance')) {
+			$this->mode = App::MODE_MAINTENANCE;
+			return true;
+		}
+
+		return false;
+	}
+
 	/**
 	 * Returns the current theme name.
 	 *
diff --git a/src/Core/Console/AutomaticInstallation.php b/src/Core/Console/AutomaticInstallation.php
index 6318b19a8..e888d5a49 100644
--- a/src/Core/Console/AutomaticInstallation.php
+++ b/src/Core/Console/AutomaticInstallation.php
@@ -5,6 +5,7 @@ namespace Friendica\Core\Console;
 use Asika\SimpleConsole\Console;
 use dba;
 use Friendica\App;
+use Friendica\Core\Install;
 
 require_once 'mod/install.php';
 require_once 'include/dba.php';
@@ -43,6 +44,8 @@ HELP;
 		$db_data = '';
 		require_once 'htconfig.php';
 
+		Install::setInstallMode();
+
 		$this->out(" Complete!\n\n");
 
 		// Check basic setup
@@ -74,7 +77,7 @@ HELP;
 		// Install database
 		$this->out("Inserting data into database...\n");
 
-		$checkResults['data'] = load_database();
+		$checkResults['data'] = Install::installDatabaseStructure();
 
 		if ($checkResults['data'] !== '') {
 			throw new \RuntimeException("ERROR: DB Database creation error. Is the DB empty?\n");
@@ -101,14 +104,14 @@ HELP;
 	{
 		$checks = [];
 
-		check_funcs($checks);
-		check_imagik($checks);
-		check_htconfig($checks);
-		check_smarty3($checks);
-		check_keys($checks);
+		Install::checkFunctions($checks);
+		Install::checkImagick($checks);
+		Install::checkHtConfig($checks);
+		Install::checkSmarty3($checks);
+		Install::checkKeys($checks);
 
 		if (!empty($app->config['php_path'])) {
-			check_php($app->config['php_path'], $checks);
+			Install::checkPHP($app->config['php_path'], $checks);
 		} else {
 			throw new \RuntimeException(" ERROR: The php_path is not set in the config. Please check the file .htconfig.php.\n");
 		}
@@ -135,7 +138,7 @@ HELP;
 		);
 
 
-		if (!dba::connect($db_host, $db_user, $db_pass, $db_data, true)) {
+		if (!dba::connect($db_host, $db_user, $db_pass, $db_data)) {
 			$result['status'] = false;
 			$result['help'] = 'Failed, please check your MySQL settings and credentials.';
 		}
diff --git a/src/Core/Install.php b/src/Core/Install.php
new file mode 100644
index 000000000..4ebc663e8
--- /dev/null
+++ b/src/Core/Install.php
@@ -0,0 +1,428 @@
+<?php
+/**
+ * @file src/Core/Install.php
+ */
+namespace Friendica\Core;
+
+use Friendica\BaseObject;
+use Friendica\App;
+use Friendica\Database\DBStructure;
+use Friendica\Object\Image;
+use Friendica\Util\Network;
+
+use Exception;
+use DOMDocument;
+
+/**
+ * Contains methods for installation purpose of Friendica
+ */
+class Install extends BaseObject
+{
+	/**
+	 * Sets the install-mode for further methods
+	 */
+	public static function setInstallMode()
+	{
+		self::getApp()->mode = App::MODE_INSTALL;
+	}
+
+	/**
+	 * Checks the current installation environment. There are optional and mandatory checks.
+	 *
+	 * @param string $phpath Optional path to the PHP binary (Default is 'php')
+	 *
+	 * @return array First element is a list of all checks and their results,
+	 *               the second element is a list of passed checks
+	 */
+	public static function check($phpath = 'php')
+	{
+		$checks = [];
+
+		self::checkFunctions($checks);
+
+		self::checkImagick($checks);
+
+		self::checkHtConfig($checks);
+
+		self::checkSmarty3($checks);
+
+		self::checkKeys($checks);
+
+		self::checkPHP($phpath, $checks);
+
+		self::checkHtAccess($checks);
+
+		$checkspassed = array_reduce($checks,
+			function ($v, $c) {
+				if ($c['require']) {
+					$v = $v && $c['status'];
+				}
+				return $v;
+			},
+			true);
+
+		return array($checks, $checkspassed);
+	}
+
+	/**
+	 * Executes the installation of Friendica in the given environment.
+	 * - Creates `.htconfig.php`
+	 * - Installs Database Structure
+	 *
+	 * @param string 	$urlpath 	Path based on the URL of Friendica (e.g. '/friendica')
+	 * @param string 	$dbhost 	Hostname/IP of the Friendica Database
+	 * @param string 	$dbuser 	Username of the Database connection credentials
+	 * @param string 	$dbpass 	Password of the Database connection credentials
+	 * @param string 	$dbdata 	Name of the Database
+	 * @param string 	$phpath 	Path to the PHP-Binary (e.g. 'php' or '/usr/bin/php')
+	 * @param string 	$timezone 	Timezone of the Friendica Installaton (e.g. 'Europe/Berlin')
+	 * @param string 	$language 	2-letter ISO 639-1 code (eg. 'en')
+	 * @param string 	$adminmail 	Mail-Adress of the administrator
+	 * @param int 		$rino		Rino-enabled (1 = true, 0 = false)
+	 */
+	public static function install($urlpath, $dbhost, $dbuser, $dbpass, $dbdata, $phpath, $timezone, $language, $adminmail, $rino = 1)
+	{
+		$tpl = get_markup_template('htconfig.tpl');
+		$txt = replace_macros($tpl,[
+			'$dbhost' => $dbhost,
+			'$dbuser' => $dbuser,
+			'$dbpass' => $dbpass,
+			'$dbdata' => $dbdata,
+			'$timezone' => $timezone,
+			'$language' => $language,
+			'$urlpath' => $urlpath,
+			'$phpath' => $phpath,
+			'$adminmail' => $adminmail,
+			'$rino' => $rino
+		]);
+
+		$result = file_put_contents('.htconfig.php', $txt);
+		if (! $result) {
+			self::getApp()->data['txt'] = $txt;
+		}
+
+		$errors = self::installDatabaseStructure();
+
+		if ($errors) {
+			self::getApp()->data['db_failed'] = $errors;
+		} else {
+			self::getApp()->data['db_installed'] = true;
+		}
+	}
+
+	/**
+	 * Adds new checks to the array $checks
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 * @param string $title The title of the current check
+	 * @param bool $status 1 = check passed, 0 = check not passed
+	 * @param bool $required 1 = check is mandatory, 0 = check is optional
+	 * @param string $help A help-string for the current check
+	 * @param string $error_msg Optional. A error message, if the current check failed
+	 */
+	private static function addCheck(&$checks, $title, $status, $required, $help, $error_msg = "")
+	{
+		$checks[] = [
+			'title' => $title,
+			'status' => $status,
+			'required' => $required,
+			'help' => $help,
+			'error_msg' => $error_msg,
+		];
+	}
+
+	/**
+	 * PHP Check
+	 *
+	 * Checks the PHP environment.
+	 *
+	 * - Checks if a PHP binary is available
+	 * - Checks if it is the CLI version
+	 * - Checks if "register_argc_argv" is enabled
+ 	 *
+	 * @param string $phpath Optional. The Path to the PHP-Binary
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkPHP(&$phpath, &$checks)
+	{
+		$passed = $passed2 = $passed3 = false;
+		if (strlen($phpath)) {
+			$passed = file_exists($phpath);
+		} else {
+			$phpath = trim(shell_exec('which php'));
+			$passed = strlen($phpath);
+		}
+		$help = "";
+		if (!$passed) {
+			$help .= L10n::t('Could not find a command line version of PHP in the web server PATH.') . EOL;
+			$help .= L10n::t("If you don't have a command line version of PHP installed on your server, you will not be able to run the background processing. See <a href='https://github.com/friendica/friendica/blob/master/doc/Install.md#set-up-the-worker'>'Setup the worker'</a>") . EOL;
+			$help .= EOL . EOL;
+			$tpl = get_markup_template('field_input.tpl');
+			$help .= replace_macros($tpl, [
+				'$field' => ['phpath', L10n::t('PHP executable path'), $phpath, L10n::t('Enter full path to php executable. You can leave this blank to continue the installation.')],
+			]);
+			$phpath = "";
+		}
+
+		self::addCheck($checks, L10n::t('Command line PHP').($passed?" (<tt>$phpath</tt>)":""), $passed, false, $help);
+
+		if ($passed) {
+			$cmd = "$phpath -v";
+			$result = trim(shell_exec($cmd));
+			$passed2 = (strpos($result, "(cli)") !== false);
+			list($result) = explode("\n", $result);
+			$help = "";
+			if (!$passed2) {
+				$help .= L10n::t("PHP executable is not the php cli binary \x28could be cgi-fgci version\x29") . EOL;
+				$help .= L10n::t('Found PHP version: ') . "<tt>$result</tt>";
+			}
+			self::addCheck($checks, L10n::t('PHP cli binary'), $passed2, true, $help);
+		}
+
+		if ($passed2) {
+			$str = autoname(8);
+			$cmd = "$phpath testargs.php $str";
+			$result = trim(shell_exec($cmd));
+			$passed3 = $result == $str;
+			$help = "";
+			if (!$passed3) {
+				$help .= L10n::t('The command line version of PHP on your system does not have "register_argc_argv" enabled.') . EOL;
+				$help .= L10n::t('This is required for message delivery to work.');
+			}
+			self::addCheck($checks, L10n::t('PHP register_argc_argv'), $passed3, true, $help);
+		}
+	}
+
+	/**
+	 * OpenSSL Check
+	 *
+	 * Checks the OpenSSL Environment
+	 *
+	 * - Checks, if the command "openssl_pkey_new" is available
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkKeys(&$checks)
+	{
+		$help = '';
+		$res = false;
+
+		if (function_exists('openssl_pkey_new')) {
+			$res = openssl_pkey_new([
+				'digest_alg' => 'sha1',
+				'private_key_bits' => 4096,
+				'encrypt_key' => false
+			]);
+		}
+
+		// Get private key
+		if (!$res) {
+			$help .= L10n::t('Error: the "openssl_pkey_new" function on this system is not able to generate encryption keys') . EOL;
+			$help .= L10n::t('If running under Windows, please see "http://www.php.net/manual/en/openssl.installation.php".');
+		}
+		self::addCheck($checks, L10n::t('Generate encryption keys'), $res, true, $help);
+	}
+
+	/**
+	 * PHP functions Check
+	 *
+	 * Checks the following PHP functions
+	 * - libCurl
+	 * - GD Graphics
+	 * - OpenSSL
+	 * - PDO or MySQLi
+	 * - mb_string
+	 * - XML
+	 * - iconv
+	 * - POSIX
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkFunctions(&$checks)
+	{
+		$ck_funcs = [];
+		self::addCheck($ck_funcs, L10n::t('libCurl PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('GD graphics PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('OpenSSL PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('PDO or MySQLi PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('mb_string PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('XML PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('iconv PHP module'), true, true, "");
+		self::addCheck($ck_funcs, L10n::t('POSIX PHP module'), true, true, "");
+
+		if (function_exists('apache_get_modules')) {
+			if (! in_array('mod_rewrite',apache_get_modules())) {
+				self::addCheck($ck_funcs, L10n::t('Apache mod_rewrite module'), false, true, L10n::t('Error: Apache webserver mod-rewrite module is required but not installed.'));
+			} else {
+				self::addCheck($ck_funcs, L10n::t('Apache mod_rewrite module'), true, true, "");
+			}
+		}
+
+		if (!function_exists('curl_init')) {
+			$ck_funcs[0]['status'] = false;
+			$ck_funcs[0]['help'] = L10n::t('Error: libCURL PHP module required but not installed.');
+		}
+		if (!function_exists('imagecreatefromjpeg')) {
+			$ck_funcs[1]['status'] = false;
+			$ck_funcs[1]['help'] = L10n::t('Error: GD graphics PHP module with JPEG support required but not installed.');
+		}
+		if (!function_exists('openssl_public_encrypt')) {
+			$ck_funcs[2]['status'] = false;
+			$ck_funcs[2]['help'] = L10n::t('Error: openssl PHP module required but not installed.');
+		}
+		if (!function_exists('mysqli_connect') && !class_exists('pdo')) {
+			$ck_funcs[3]['status'] = false;
+			$ck_funcs[3]['help'] = L10n::t('Error: PDO or MySQLi PHP module required but not installed.');
+		}
+		if (!function_exists('mysqli_connect') && class_exists('pdo') && !in_array('mysql', PDO::getAvailableDrivers())) {
+			$ck_funcs[3]['status'] = false;
+			$ck_funcs[3]['help'] = L10n::t('Error: The MySQL driver for PDO is not installed.');
+		}
+		if (!function_exists('mb_strlen')) {
+			$ck_funcs[4]['status'] = false;
+			$ck_funcs[4]['help'] = L10n::t('Error: mb_string PHP module required but not installed.');
+		}
+		if (!function_exists('iconv_strlen')) {
+			$ck_funcs[6]['status'] = false;
+			$ck_funcs[6]['help'] = L10n::t('Error: iconv PHP module required but not installed.');
+		}
+		if (!function_exists('posix_kill')) {
+			$ck_funcs[7]['status'] = false;
+			$ck_funcs[7]['help'] = L10n::t('Error: POSIX PHP module required but not installed.');
+		}
+
+		$checks = array_merge($checks, $ck_funcs);
+
+		// check for XML DOM Documents being able to be generated
+		try {
+			$xml = new DOMDocument();
+		} catch (Exception $e) {
+			$ck_funcs[5]['status'] = false;
+			$ck_funcs[5]['help'] = L10n::t('Error, XML PHP module required but not installed.');
+		}
+	}
+
+	/**
+	 * ".htconfig.php" - Check
+	 *
+	 * Checks if it's possible to create the ".htconfig.php"
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkHtConfig(&$checks)
+	{
+		$status = true;
+		$help = "";
+		if ((file_exists('.htconfig.php') && !is_writable('.htconfig.php')) ||
+			(!file_exists('.htconfig.php') && !is_writable('.'))) {
+
+			$status = false;
+			$help = L10n::t('The web installer needs to be able to create a file called ".htconfig.php" in the top folder of your web server and it is unable to do so.') . EOL;
+			$help .= L10n::t('This is most often a permission setting, as the web server may not be able to write files in your folder - even if you can.') . EOL;
+			$help .= L10n::t('At the end of this procedure, we will give you a text to save in a file named .htconfig.php in your Friendica top folder.') . EOL;
+			$help .= L10n::t('You can alternatively skip this procedure and perform a manual installation. Please see the file "INSTALL.txt" for instructions.') . EOL;
+		}
+
+		self::addCheck($checks, L10n::t('.htconfig.php is writable'), $status, false, $help);
+
+	}
+
+	/**
+	 * Smarty3 Template Check
+	 *
+	 * Checks, if the directory of Smarty3 is writable
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkSmarty3(&$checks)
+	{
+		$status = true;
+		$help = "";
+		if (!is_writable('view/smarty3')) {
+
+			$status = false;
+			$help = L10n::t('Friendica uses the Smarty3 template engine to render its web views. Smarty3 compiles templates to PHP to speed up rendering.') . EOL;
+			$help .= L10n::t('In order to store these compiled templates, the web server needs to have write access to the directory view/smarty3/ under the Friendica top level folder.') . EOL;
+			$help .= L10n::t("Please ensure that the user that your web server runs as \x28e.g. www-data\x29 has write access to this folder.") . EOL;
+			$help .= L10n::t("Note: as a security measure, you should give the web server write access to view/smarty3/ only--not the template files \x28.tpl\x29 that it contains.") . EOL;
+		}
+
+		self::addCheck($checks, L10n::t('view/smarty3 is writable'), $status, true, $help);
+	}
+
+	/**
+	 * ".htaccess" - Check
+	 *
+	 * Checks, if "url_rewrite" is enabled in the ".htaccess" file
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkHtAccess(&$checks)
+	{
+		$status = true;
+		$help = "";
+		$error_msg = "";
+		if (function_exists('curl_init')) {
+			$test = Network::fetchUrlFull(System::baseUrl() . "/install/testrewrite");
+
+			$url = normalise_link(System::baseUrl() . "/install/testrewrite");
+			if ($test['body'] != "ok") {
+				$test = Network::fetchUrlFull($url);
+			}
+
+			if ($test['body'] != "ok") {
+				$status = false;
+				$help = L10n::t('Url rewrite in .htaccess is not working. Check your server configuration.');
+				$error_msg = [];
+				$error_msg['head'] = L10n::t('Error message from Curl when fetching');
+				$error_msg['url'] = $test['redirect_url'];
+				$error_msg['msg'] = $test['error'];
+			}
+			self::addCheck($checks, L10n::t('Url rewrite is working'), $status, true, $help, $error_msg);
+		} else {
+			// cannot check modrewrite if libcurl is not installed
+			/// @TODO Maybe issue warning here?
+		}
+	}
+
+	/**
+	 * Imagick Check
+	 *
+	 * Checks, if the imagick module is available
+	 *
+	 * @param array $checks The list of all checks (by-ref parameter!)
+	 */
+	public static function checkImagick(&$checks)
+	{
+		$imagick = false;
+		$gif = false;
+
+		if (class_exists('Imagick')) {
+			$imagick = true;
+			$supported = Image::supportedTypes();
+			if (array_key_exists('image/gif', $supported)) {
+				$gif = true;
+			}
+		}
+		if ($imagick == false) {
+			self::addCheck($checks, L10n::t('ImageMagick PHP extension is not installed'), $imagick, false, "");
+		} else {
+			self::addCheck($checks, L10n::t('ImageMagick PHP extension is installed'), $imagick, false, "");
+			if ($imagick) {
+				self::addCheck($checks, L10n::t('ImageMagick supports GIF'), $gif, false, "");
+			}
+		}
+	}
+
+	/**
+	 * Installs the Database structure
+	 *
+	 * @return string A possible error
+	 */
+	public static function installDatabaseStructure()
+	{
+		$errors = DBStructure::update(false, true, true);
+
+		return $errors;
+	}
+}