diff --git a/core/config.class.inc.php b/core/config.class.inc.php
index 79afb1620..6c9a4677c 100644
--- a/core/config.class.inc.php
+++ b/core/config.class.inc.php
@@ -532,7 +532,7 @@ class Config
 			'type' => 'string',
 			'description' => 'Source directory for the datamodel files. (which gets compiled to env-production).',
 			// examples... not used
-			'default' => 'datamodels/latest',
+			'default' => '',
 			'value' => '',
 			'source_of_value' => '',
 			'show_in_conf_sample' => true,
@@ -1420,7 +1420,7 @@ class Config
 	/**
 	 * Helper function to initialize a configuration from the page arguments
 	 */
-	public function UpdateFromParams($aParamValues, $sModulesDir = null)
+	public function UpdateFromParams($aParamValues, $sModulesDir = null, $bPreserveModuleSettings = false)
 	{
 		if (isset($aParamValues['application_path']))
 		{
@@ -1469,7 +1469,7 @@ class Config
 			// Merge the values with the ones provided by the modules
 			// Make sure when don't load the same file twice...
 	
-			$aModules = ModuleDiscovery::GetAvailableModules(APPROOT, $sModulesDir);
+			$aModules = ModuleDiscovery::GetAvailableModules(array(APPROOT.$sModulesDir));
 			foreach($aModules as $sModuleId => $aModuleInfo)
 			{
 				list($sModuleName, $sModuleVersion) = ModuleDiscovery::GetModuleName($sModuleId);
@@ -1489,10 +1489,17 @@ class Config
 					}
 					if (isset($aModuleInfo['settings']))
 					{
+						list($sName, $sVersion) = ModuleDiscovery::GetModuleName($sModuleId);
 						foreach($aModuleInfo['settings'] as $sProperty => $value)
 						{
-							list($sName, $sVersion) = ModuleDiscovery::GetModuleName($sModuleId);
-							$this->SetModuleSetting($sName, $sProperty, $value);
+							if ($bPreserveModuleSettings && isset($this->m_aModuleSettings[$sName][$sProperty]))
+							{
+								// Do nothing keep the original value
+							}
+							else
+							{
+								$this->SetModuleSetting($sName, $sProperty, $value);
+							}
 						}
 					}
 					if (isset($aModuleInfo['installer']))
diff --git a/images/extension.png b/images/extension.png
new file mode 100644
index 000000000..1460b8d49
Binary files /dev/null and b/images/extension.png differ
diff --git a/setup/ajax.dataloader.php b/setup/ajax.dataloader.php
index 3ea53ac7c..dcaa60c19 100644
--- a/setup/ajax.dataloader.php
+++ b/setup/ajax.dataloader.php
@@ -136,18 +136,36 @@ try
 	switch($sOperation)
 	{
 		case 'async_action':
-		require_once(APPROOT.'/setup/wizardcontroller.class.inc.php');
-		require_once(APPROOT.'/setup/wizardsteps.class.inc.php');
+		ini_set('max_execution_time', max(240, ini_get('max_execution_time')));
+		// While running the setup it is desirable to see any error that may happen
+		ini_set('display_errors', true);
+		ini_set('display_startup_errors', true);
 		
-		$sClass = utils::ReadParam('step_class', '');
-		$sState = utils::ReadParam('step_state', '');
-		$sActionCode = utils::ReadParam('code', '');
-		$aParams = utils::ReadParam('params', array(), false, 'raw_data');
-		$oPage = new ajax_page('');
-		$oDummyController = new WizardController('');
-		$oStep = new $sClass($oDummyController, $sState);
-		$oStep->AsyncAction($oPage, $sActionCode, $aParams);
-		$oPage->output();
+		$sConfigFile = utils::GetConfigFilePath();
+		if (file_exists($sConfigFile) && !is_writable($sConfigFile))
+		{
+			$oPage->error("<b>Error:</b> the configuration file '".$sConfigFile."' already exists and cannot be overwritten.");
+			$oPage->p("The wizard cannot modify the configuration file for you. If you want to upgrade ".ITOP_APPLICATION.", make sure that the file '<b>".realpath($sConfigFile)."</b>' can be modified by the web server.");
+			$oPage->output();
+		}
+		else
+		{
+			require_once(APPROOT.'/setup/wizardcontroller.class.inc.php');
+			require_once(APPROOT.'/setup/wizardsteps.class.inc.php');
+			
+			$sClass = utils::ReadParam('step_class', '');
+			$sState = utils::ReadParam('step_state', '');
+			$sActionCode = utils::ReadParam('code', '');
+			$aParams = utils::ReadParam('params', array(), false, 'raw_data');
+			$oPage = new ajax_page('');
+			$oDummyController = new WizardController('');
+			if (is_subclass_of($sClass, 'WizardStep'))
+			{
+				$oStep = new $sClass($oDummyController, $sState);
+				$oStep->AsyncAction($oPage, $sActionCode, $aParams);
+			}
+			$oPage->output();
+		}
 		break;
 
 		//////////////////////////////
diff --git a/setup/applicationinstaller.class.inc.php b/setup/applicationinstaller.class.inc.php
index ccb7a7d32..d0268baf2 100644
--- a/setup/applicationinstaller.class.inc.php
+++ b/setup/applicationinstaller.class.inc.php
@@ -126,7 +126,7 @@ class ApplicationInstaller
 				$aPreinstall = $this->oParams->Get('preinstall');
 				$aCopies = $aPreinstall['copies'];
 
-				// disabled - $sReport = self::DoCopy($aCopies);
+				$sReport = self::DoCopy($aCopies);
 				$sReport = "copy disabled...";
 
 				$aResult = array(
@@ -167,7 +167,8 @@ class ApplicationInstaller
 				
 				case 'compile':
 				$aSelectedModules = $this->oParams->Get('selected_modules');
-				$sSourceDir = $this->oParams->Get('source_dir', 'datamodel');
+				$sSourceDir = $this->oParams->Get('source_dir', 'datamodels/latest');
+				$sExtensionDir = $this->oParams->Get('extensions_dir', 'extensions');
 				$sTargetEnvironment = $this->oParams->Get('target_env', '');
 				if ($sTargetEnvironment == '')
 				{
@@ -190,7 +191,7 @@ class ApplicationInstaller
 					}
 				}
 						
-				self::DoCompile($aSelectedModules, $sSourceDir, $sTargetDir, $sWorkspaceDir, $bUseSymbolicLinks);
+				self::DoCompile($aSelectedModules, $sSourceDir, $sExtensionDir, $sTargetDir, $sWorkspaceDir, $bUseSymbolicLinks);
 				
 				$aResult = array(
 					'status' => self::OK,
@@ -215,8 +216,9 @@ class ApplicationInstaller
 				$sDBPwd = $aDBParams['pwd'];
 				$sDBName = $aDBParams['name'];
 				$sDBPrefix = $aDBParams['prefix'];
+				$bOldAddon = $this->oParams->Get('old_addon', false);
 				
-				self::DoUpdateDBSchema($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment);
+				self::DoUpdateDBSchema($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment, $bOldAddon);
 				
 				$aResult = array(
 					'status' => self::OK,
@@ -247,8 +249,12 @@ class ApplicationInstaller
 				$sAdminLanguage = $aAdminParams['language'];
 				$sLanguage = $this->oParams->Get('language');
 				$aSelectedModules = $this->oParams->Get('selected_modules', array());
+				$sDataModelVersion = $this->oParams->Get('datamodel_version', '0.0.0');
+				$bOldAddon = $this->oParams->Get('old_addon', false);
+				$sSourceDir = $this->oParams->Get('source_dir', '');
 				
-				self::AfterDBCreate($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sAdminUser, $sAdminPwd, $sAdminLanguage, $sLanguage, $aSelectedModules, $sTargetEnvironment);
+				self::AfterDBCreate($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sAdminUser,
+									$sAdminPwd, $sAdminLanguage, $sLanguage, $aSelectedModules, $sTargetEnvironment, $bOldAddon, $sDataModelVersion, $sSourceDir);
 				
 				$aResult = array(
 					'status' => self::OK,
@@ -277,8 +283,9 @@ class ApplicationInstaller
 				$sDBName = $aDBParams['name'];
 				$sDBPrefix = $aDBParams['prefix'];
 				$aFiles = $this->oParams->Get('files', array());
+				$bOldAddon = $this->oParams->Get('old_addon', false);
 				
-				self::DoLoadFiles($aSelectedModules, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment);
+				self::DoLoadFiles($aSelectedModules, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment, $bOldAddon);
 				
 				$aResult = array(
 					'status' => self::INFO,
@@ -306,8 +313,11 @@ class ApplicationInstaller
 				$sUrl = $this->oParams->Get('url', '');
 				$sLanguage = $this->oParams->Get('language', '');
 				$aSelectedModules = $this->oParams->Get('selected_modules', array());
+				$bOldAddon = $this->oParams->Get('old_addon', false);
+				$sSourceDir = $this->oParams->Get('source_dir', '');
+				$sPreviousConfigFile = $this->oParams->Get('previous_configuration_file', '');
 				
-				self::DoCreateConfig($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sUrl, $sLanguage, $aSelectedModules, $sTargetEnvironment);
+				self::DoCreateConfig($sMode, $sTargetDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sUrl, $sLanguage, $aSelectedModules, $sTargetEnvironment, $bOldAddon, $sSourceDir, $sPreviousConfigFile);
 				
 				$aResult = array(
 					'status' => self::INFO,
@@ -338,6 +348,9 @@ class ApplicationInstaller
 				'next-step-label' => '',
 				'percentage-completed' => 100,
 			);
+			
+			SetupPage::log_error('An exception occurred: '.$e->getMessage());
+			SetupPage::log("Stack trace:\n".$e->getTraceAsString());
 		}
 		return $aResult;
 	}
@@ -374,7 +387,7 @@ class ApplicationInstaller
 	}
 
 	
-	protected static function DoCompile($aSelectedModules, $sSourceDir, $sTargetDir, $sWorkspaceDir = '', $bUseSymbolicLinks = false)
+	protected static function DoCompile($aSelectedModules, $sSourceDir, $sExtensionDir, $sTargetDir, $sWorkspaceDir = '', $bUseSymbolicLinks = false)
 	{
 		SetupPage::log_info("Compiling data model.");
 
@@ -388,6 +401,7 @@ class ApplicationInstaller
 		}		
 
 		$sSourcePath = APPROOT.$sSourceDir;
+		$sExtensionsPath = APPROOT.$sExtensionDir;
 		$sTargetPath = APPROOT.$sTargetDir;
 		if (!is_dir($sSourcePath))
 		{
@@ -407,7 +421,7 @@ class ApplicationInstaller
 			}
 		}
 
-		$oFactory = new ModelFactory($sSourcePath);
+		$oFactory = new ModelFactory(array($sSourcePath, $sExtensionsPath));
 		$aModules = $oFactory->FindModules();
 
 		foreach($aModules as $foo => $oModule)
@@ -441,13 +455,24 @@ class ApplicationInstaller
 		}
 		else
 		{
-			$oMFCompiler = new MFCompiler($oFactory, $sSourcePath);
+			$oMFCompiler = new MFCompiler($oFactory);
 			$oMFCompiler->Compile($sTargetPath, null, $bUseSymbolicLinks);
 			SetupPage::log_info("Data model successfully compiled to '$sTargetPath'.");
 		}
+		
+		// Special case to patch a ugly patch in itop-config-mgmt
+		$sFileToPatch = $sTargetPath.'/itop-config-mgmt-1.0.0/model.itop-config-mgmt.php';
+		if (file_exists($sFileToPatch))
+		{
+			$sContent = file_get_contents($sFileToPatch);
+			
+			$sContent = str_replace("require_once(APPROOT.'modules/itop-welcome-itil/model.itop-welcome-itil.php');", "//\n// The line below is no longer needed in iTop 2.0 -- patched by the setup program\n// require_once(APPROOT.'modules/itop-welcome-itil/model.itop-welcome-itil.php');", $sContent);
+			
+			file_put_contents($sFileToPatch, $sContent);
+		}
 	}
 	
-	protected static function DoUpdateDBSchema($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment  = '')
+	protected static function DoUpdateDBSchema($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment  = '', $bOldAddon = false)
 	{
 		SetupPage::log_info("Update Database Schema for environment '$sTargetEnvironment'.");
 
@@ -461,7 +486,14 @@ class ApplicationInstaller
 			'db_prefix' => $sDBPrefix,
 		);
 		$oConfig->UpdateFromParams($aParamValues, $sModulesDir);
-
+		if ($bOldAddon)
+		{
+			// Old version of the add-on for backward compatibility with pre-2.0 data models
+			$oConfig->SetAddons(array(
+				'user rights' => 'addons/userrights/userrightsprofile.db.class.inc.php',
+			));
+		}
+		
 		$oProductionEnv = new RunTimeEnvironment($sTargetEnvironment);
 		$oProductionEnv->InitDataModel($oConfig, true);  // load data model only
 
@@ -472,7 +504,7 @@ class ApplicationInstaller
 		SetupPage::log_info("Database Schema Successfully Updated for environment '$sTargetEnvironment'.");
 	}
 	
-	protected static function AfterDBCreate($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sAdminUser, $sAdminPwd, $sAdminLanguage, $sLanguage, $aSelectedModules, $sTargetEnvironment  = '')
+	protected static function AfterDBCreate($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sAdminUser, $sAdminPwd, $sAdminLanguage, $sLanguage, $aSelectedModules, $sTargetEnvironment, $bOldAddon, $sDataModelVersion, $sSourceDir)
 	{
 
 		SetupPage::log_info('After Database Creation');
@@ -487,18 +519,27 @@ class ApplicationInstaller
 			'db_prefix' => $sDBPrefix,
 		);
 		$oConfig->UpdateFromParams($aParamValues, $sModulesDir);
-
+		if ($bOldAddon)
+		{
+			// Old version of the add-on for backward compatibility with pre-2.0 data models
+			$oConfig->SetAddons(array(
+				'user rights' => 'addons/userrights/userrightsprofile.db.class.inc.php',
+			));
+		}
+		$oConfig->Set('source_dir', $sSourceDir); // Needed by RecordInstallation below
+		
 		$oProductionEnv = new RunTimeEnvironment($sTargetEnvironment);
-		$oProductionEnv->InitDataModel($oConfig, false);  // load data model and connect to the database
+		$oProductionEnv->InitDataModel($oConfig, true);  // load data model and connect to the database
+		
 		self::$bMetaModelStarted = true; // No need to reload the final MetaModel in case the installer runs synchronously 
 		
 		// Perform here additional DB setup... profiles, etc...
 		//
-		$aAvailableModules = $oProductionEnv->AnalyzeInstallation(MetaModel::GetConfig(), $sModulesDir);
+		$aAvailableModules = $oProductionEnv->AnalyzeInstallation(MetaModel::GetConfig(), APPROOT.$sModulesDir);
 		foreach($aAvailableModules as $sModuleId => $aModule)
 		{
 			if (($sModuleId != ROOT_MODULE) && in_array($sModuleId, $aSelectedModules) &&
-			     isset($aAvailableModules[$sModuleId]['installer']) )
+				isset($aAvailableModules[$sModuleId]['installer']) )
 			{
 				$sModuleInstallerClass = $aAvailableModules[$sModuleId]['installer'];
 				SetupPage::log_info("Calling Module Handler: $sModuleInstallerClass::AfterDatabaseCreation(oConfig, {$aModule['version_db']}, {$aModule['version_code']})");
@@ -555,7 +596,7 @@ class ApplicationInstaller
 			}
 		}
 
-		if (!$oProductionEnv->RecordInstallation($oConfig, $aSelectedModules, $sModulesDir))
+		if (!$oProductionEnv->RecordInstallation($oConfig, $sDataModelVersion, $aSelectedModules, $sModulesDir))
 		{
 			throw new Exception("Failed to record the installation information");
 		}
@@ -591,7 +632,7 @@ class ApplicationInstaller
 		}
 	}
 	
-	protected static function DoLoadFiles($aSelectedModules, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment = '')
+	protected static function DoLoadFiles($aSelectedModules, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sTargetEnvironment = '', $bOldAddon = false)
 	{
 		$aParamValues = array(
 			'db_server' => $sDBServer,
@@ -604,7 +645,14 @@ class ApplicationInstaller
 		$oConfig = new Config();
 
 		$oConfig->UpdateFromParams($aParamValues, $sModulesDir);
-
+		if ($bOldAddon)
+		{
+			// Old version of the add-on for backward compatibility with pre-2.0 data models
+			$oConfig->SetAddons(array(
+				'user rights' => 'addons/userrights/userrightsprofile.db.class.inc.php',
+			));
+		}
+		
 		//Load the MetaModel if needed (asynchronous mode)
 		if (!self::$bMetaModelStarted)
 		{
@@ -624,7 +672,7 @@ class ApplicationInstaller
 
 		$aFiles = array();		
 		$oProductionEnv = new RunTimeEnvironment();
-		$aAvailableModules = $oProductionEnv->AnalyzeInstallation($oConfig, $sModulesDir);
+		$aAvailableModules = $oProductionEnv->AnalyzeInstallation($oConfig, APPROOT.$sModulesDir);
 		foreach($aAvailableModules as $sModuleId => $aModule)
 		{
 			if (($sModuleId != ROOT_MODULE))
@@ -658,7 +706,7 @@ class ApplicationInstaller
 	    SetupPage::log_info("ending data load session");
 	}
 	
-	protected static function DoCreateConfig($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sUrl, $sLanguage, $aSelectedModules, $sTargetEnvironment  = '')
+	protected static function DoCreateConfig($sMode, $sModulesDir, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix, $sUrl, $sLanguage, $aSelectedModules, $sTargetEnvironment, $bOldAddon, $sSourceDir, $sPreviousConfigFile)
 	{	
 		$aParamValues = array(
 			'db_server' => $sDBServer,
@@ -668,20 +716,46 @@ class ApplicationInstaller
 			'new_db_name' => $sDBName,
 			'db_prefix' => $sDBPrefix,
 			'application_path' => $sUrl,
-			'mode' => $sMode,
 			'language' => $sLanguage,
 			'selected_modules' => implode(',', $aSelectedModules), 
 		);
 		
-		$oConfig = new Config();
+		$bPreserveModuleSettings = false;
+		if ($sMode == 'upgrade')
+		{
+			try 
+			{
+				$oOldConfig = new Config($sPreviousConfigFile);
+				$oConfig = clone($oOldConfig);
+				$bPreserveModuleSettings = true;
+			}
+			catch(Exception $e)
+			{
+				// In case the previous configuration is corrupted... start with a blank new one
+				$oConfig = new Config();
+			}
+		}
+		else
+		{
+			$oConfig = new Config();
+		}
+		
 		
 		// Migration: force utf8_unicode_ci as the collation to make the global search
 		// NON case sensitive
 		$oConfig->SetDBCollation('utf8_unicode_ci');
 		
 		// Final config update: add the modules
-		$oConfig->UpdateFromParams($aParamValues, $sModulesDir);
-
+		$oConfig->UpdateFromParams($aParamValues, $sModulesDir, $bPreserveModuleSettings);
+		if ($bOldAddon)
+		{
+			// Old version of the add-on for backward compatibility with pre-2.0 data models
+			$oConfig->SetAddons(array(
+				'user rights' => 'addons/userrights/userrightsprofile.db.class.inc.php',
+			));
+		}
+		$oConfig->Set('source_dir', $sSourceDir);
+		
 		// Make sure the root configuration directory exists
 		if (!file_exists(APPCONF))
 		{
@@ -700,5 +774,7 @@ class ApplicationInstaller
 			
 		// try to make the final config file read-only
 		@chmod($sConfigFile, 0444); // Read-only for owner and group, nothing for others
+		// Ready to go !!
+		MetaModel::ResetCache($sTargetEnvironment);
 	}
 }
diff --git a/setup/compiler.class.inc.php b/setup/compiler.class.inc.php
index 2f9a88a35..33d3986c2 100644
--- a/setup/compiler.class.inc.php
+++ b/setup/compiler.class.inc.php
@@ -27,15 +27,14 @@ class DOMFormatException extends Exception
 class MFCompiler
 {
 	protected $oFactory;
-	protected $sSourceDir;
+	protected $aSourceDirs;
 
 	protected $aRootClasses;
 	protected $aLog;
 
-	public function __construct($oModelFactory, $sSourceDir)
+	public function __construct($oModelFactory)
 	{
 		$this->oFactory = $oModelFactory;
-		$this->sSourceDir = $sSourceDir;
 
 		$this->aLog = array();
 	}
@@ -97,7 +96,7 @@ class MFCompiler
 			$sModuleVersion = $oModule->GetVersion();
 		
 			$sModuleRootDir = realpath($oModule->GetRootDir());
-			$sRelativeDir = substr($sModuleRootDir, strlen($this->sSourceDir) + 1);
+			$sRelativeDir = basename($sModuleRootDir);
 		
 			// Push the other module files
 			SetupUtils::copydir($sModuleRootDir, $sTargetDir.'/'.$sRelativeDir, $bUseSymbolicLinks);
@@ -878,11 +877,12 @@ EOF;
 			{
 				$sPHP .= "\nrequire_once('$sIncludeFile'); // Implementation of the class $sParentClass\n";
 			}
-			$sFullPath =  $this->sSourceDir.'/'.$sModuleRelativeDir.'/'.$sIncludeFile;
-			if (!file_exists($sFullPath))
-			{
-				throw new Exception("Failed to process class '".$oClass->getAttribute('id')."', from '$sModuleRelativeDir'. The required include file: '$sFullPath' does not exist.");
-			}
+//TODO fix this !!!
+//			$sFullPath =  $this->sSourceDir.'/'.$sModuleRelativeDir.'/'.$sIncludeFile;
+//			if (!file_exists($sFullPath))
+//			{
+//				throw new Exception("Failed to process class '".$oClass->getAttribute('id')."', from '$sModuleRelativeDir'. The required include file: '$sFullPath' does not exist.");
+//			}
 		}
 		else
 		{
@@ -1151,7 +1151,6 @@ EOF;
 
 		$sPHP =
 <<<EOF
-
 //
 // List of constant profiles
 // - used by the class URP_Profiles at setup (create/update/delete records)
diff --git a/setup/index-new.php b/setup/index-new.php
index 9e3f96ca7..b3b331265 100644
--- a/setup/index-new.php
+++ b/setup/index-new.php
@@ -30,5 +30,12 @@ require_once(APPROOT.'/setup/setuppage.class.inc.php');
 require_once(APPROOT.'/setup/wizardcontroller.class.inc.php');
 require_once(APPROOT.'/setup/wizardsteps.class.inc.php');
 
+clearstatcache(); // Make sure we know what we are doing !
+// Set a long (at least 4 minutes) execution time for the setup to avoid timeouts during this phase
+ini_set('max_execution_time', max(240, ini_get('max_execution_time')));
+// While running the setup it is desirable to see any error that may happen
+ini_set('display_errors', true);
+ini_set('display_startup_errors', true);
+
 $oWizard = new WizardController('WizStepWelcome');
 $oWizard->Run();
diff --git a/setup/modelfactory.class.inc.php b/setup/modelfactory.class.inc.php
index e4ba50c9b..e3e1cf026 100644
--- a/setup/modelfactory.class.inc.php
+++ b/setup/modelfactory.class.inc.php
@@ -1076,7 +1076,7 @@ EOF
 	 */
 	public function FindModules($sSubDirectory = '')
 	{
-		$aAvailableModules = ModuleDiscovery::GetAvailableModules($this->sRootDir, $sSubDirectory);
+		$aAvailableModules = ModuleDiscovery::GetAvailableModules($this->sRootDir, array($sSubDirectory));
 		$aResult = array();
 		foreach($aAvailableModules as $sId => $aModule)
 		{
diff --git a/setup/modulediscovery.class.inc.php b/setup/modulediscovery.class.inc.php
index 0f311fa2d..894ee4cd6 100644
--- a/setup/modulediscovery.class.inc.php
+++ b/setup/modulediscovery.class.inc.php
@@ -30,11 +30,8 @@ class ModuleDiscovery
 	);
 	
 
-	// Cache the results and the source directory
-	// Note that, as class can be declared within the module files, they cannot be loaded twice.
-	// Then the following assumption is made: within the same execution page, the module
-	// discovery CANNOT be executed on several different paths
-	protected static $m_sModulesRoot = null;
+	// Cache the results and the source directories
+	protected static $m_aSearchDirs = null;
 	protected static $m_aModules = array();
 
 	// All the entries below are list of file paths relative to the module directory
@@ -164,45 +161,44 @@ class ModuleDiscovery
 	/**
 	 * Search (on the disk) for all defined iTop modules, load them and returns the list (as an array)
 	 * of the possible iTop modules to install
-	 * @param sRootDir Application root directory
-	 * @param sSearchDir Directory to search (relative to root dir)
+	 * @param aSearchDirs Array of directories to search (absolute paths)
 	 * @return Hash A big array moduleID => ModuleData
 	 */
-	public static function GetAvailableModules($sRootDir, $sSearchDir, $oP = null)
+	public static function GetAvailableModules($aSearchDirs, $oP = null)
 	{
-		$sLookupDir = realpath($sRootDir.'/'.$sSearchDir);
-		
-		if (self::$m_sModulesRoot != $sLookupDir)
+		if (self::$m_aSearchDirs != $aSearchDirs)
 		{
 			self::ResetCache();
 		}
 		
-		if (is_null(self::$m_sModulesRoot))
+		if (is_null(self::$m_aSearchDirs))
 		{
-			// First call
-			//
-			if ($sLookupDir == '')
+			self::$m_aSearchDirs = $aSearchDirs;
+			
+			// Not in cache, let's scan the disk
+			foreach($aSearchDirs as $sSearchDir)
 			{
-				throw new Exception("Invalid directory '$sRootDir/$sSearchDir'");
+				$sLookupDir = realpath($sSearchDir);			
+				if ($sLookupDir == '')
+				{
+					throw new Exception("Invalid directory '$sSearchDir'");
+				}
+	
+				clearstatcache();
+				self::ListModuleFiles(basename($sSearchDir), dirname($sSearchDir));
 			}
-			self::$m_sModulesRoot = $sLookupDir;
-
-			clearstatcache();
-			self::ListModuleFiles($sSearchDir, $sRootDir);
 			return self::GetModules($oP);
 		}
 		else
 		{
 			// Reuse the previous results
-			//
 			return self::GetModules($oP);
 		}
 	}
 	
 	public static function ResetCache()
 	{
-		self::$m_sModulesRoot = null;
-		self::$m_sModulesRoot = null;
+		self::$m_aSearchDirs = null;
 		self::$m_aModules = array();
 	}
 
@@ -233,6 +229,8 @@ class ModuleDiscovery
 	 */    
 	protected static function ListModuleFiles($sRelDir, $sRootDir)
 	{
+		static $iDummyClassIndex = 0;
+		static $aDefinedClasses = array();
 		$sDirectory = $sRootDir.'/'.$sRelDir;
 		
 		if ($hDir = opendir($sDirectory))
@@ -253,15 +251,35 @@ class ModuleDiscovery
 					self::SetModulePath($sRelDir);
 					try
 					{
-						//echo "<p>Loading: $sDirectory/$sFile...</p>\n";
-						//SetupPage::log_info("Discovered module $sFile");
-						require($sDirectory.'/'.$sFile); // WARNING require_once will NOT work IIF doing an unattended installation WITH symbolic links
-														 // since datamodel/xxx/module.xxx.php and env-production/xxx/module.xxx.php are actually the same file (= inode)
+						$sModuleFileContents = file_get_contents($sDirectory.'/'.$sFile);
+						$sModuleFileContents = str_replace(array('<?php', '?>'), '', $sModuleFileContents);
+						$sModuleFileContents = str_replace('__FILE__', "'".addslashes($sDirectory.'/'.$sFile)."'", $sModuleFileContents);
+						preg_match_all('/class ([A-Za-z0-9_]+) extends ([A-Za-z0-9_]+)/', $sModuleFileContents, $aMatches);
+						//print_r($aMatches);
+						$idx = 0;
+						foreach($aMatches[1] as $sClassName)
+						{
+							if (class_exists($sClassName))
+							{
+								// rename the class inside the code to prevent a "duplicate class" declaration
+								// and change its parent class as well so that nobody will find it and try to execute it
+								$sModuleFileContents = str_replace($sClassName.' extends '.$aMatches[2][$idx], $sClassName.'_'.($iDummyClassIndex++).' extends DummyHandler', $sModuleFileContents);
+							}
+							$idx++;
+						}
+						$bRet = eval($sModuleFileContents);
+						
+						if ($bRet === false)
+						{
+							SetupPage::log_warning("Eval of $sRelDir/$sFile returned false");
+						}
+						
 						//echo "<p>Done.</p>\n";
 					}
 					catch(Exception $e)
 					{
 						// Continue...
+						SetupPage::log_warning("Eval of $sRelDir/$sFile caused an exception: ".$e->getMessage());
 					}
 				}
 			}
@@ -279,6 +297,41 @@ class ModuleDiscovery
  *  the declaration of a module invokes SetupWebPage::AddModule()
  *  whereas the new form is ModuleDiscovery::AddModule()
  */  
-class SetupWebPage extends ModuleDiscovery{}
+class SetupWebPage extends ModuleDiscovery
+{
+	// For backward compatibility with old modules...
+	public static function log_error($sText)
+	{
+		SetupPage::log_error($sText);
+	}
 
-?>
+	public static function log_warning($sText)
+	{
+		SetupPage::log_warning($sText);
+	}
+
+	public static function log_info($sText)
+	{
+		SetupPage::log_info($sText);
+	}
+
+	public static function log_ok($sText)
+	{
+		SetupPage::log_ok($sText);
+	}
+
+	public static function log($sText)
+	{
+		SetupPage::log($sText);
+	}	
+}
+		
+/** Ugly patch !!!
+ * In order to be able to analyse / load several times
+ * the same module file, we rename the class (to avoid duplicate class definitions)
+ * and we make the class extends the dummy class below in order to "deactivate" completely
+ * the class (in case some piece of code enumerate the classes derived from a well known class)
+ * Note that this will not work if someone enumerates the classes that implement a given interface
+ */
+class DummyHandler {
+}
diff --git a/setup/runtimeenv.class.inc.php b/setup/runtimeenv.class.inc.php
index 556ab881e..1fc3ef4dd 100644
--- a/setup/runtimeenv.class.inc.php
+++ b/setup/runtimeenv.class.inc.php
@@ -32,6 +32,7 @@ define ('MODULE_ACTION_OPTIONAL', 1);
 define ('MODULE_ACTION_MANDATORY', 2);
 define ('MODULE_ACTION_IMPOSSIBLE', 3);
 define ('ROOT_MODULE', '_Root_'); // Convention to store IN MEMORY the name/version of the root module i.e. application
+define ('DATAMODEL_MODULE', 'datamodel'); // Convention to store the version of the datamodel
 
 class RunTimeEnvironment
 {
@@ -91,7 +92,8 @@ class RunTimeEnvironment
 	/**
 	 * Analyzes the current installation and the possibilities
 	 * 
-	 * @param $oConfig Config Defines the target environment (DB)
+	 * @param Config $oConfig Defines the target environment (DB)
+	 * @param mixed $modulesPath Either a single string or an array of absolute paths
 	 * @return hash Array with the following format:
 	 * array =>
 	 *     'iTop' => array(
@@ -115,7 +117,7 @@ class RunTimeEnvironment
 	 *     )
 	 * )
 	 */     
-	public function AnalyzeInstallation($oConfig, $sModulesRelativePath)
+	public function AnalyzeInstallation($oConfig, $modulesPath)
 	{
 		$aRes = array(
 			ROOT_MODULE => array(
@@ -126,7 +128,8 @@ class RunTimeEnvironment
 			)
 		);
 	
-		$aModules = ModuleDiscovery::GetAvailableModules(APPROOT, $sModulesRelativePath);
+		$aDirs = is_array($modulesPath) ? $modulesPath : array($modulesPath);
+		$aModules = ModuleDiscovery::GetAvailableModules($aDirs);
 		foreach($aModules as $sModuleId => $aModuleInfo)
 		{
 			list($sModuleName, $sModuleVersion) = ModuleDiscovery::GetModuleName($sModuleId);
@@ -137,7 +140,8 @@ class RunTimeEnvironment
 			if ($sModuleVersion == '')
 			{
 				// The version must not be empty (it will be used as a criteria to determine wether a module has been installed or not)
-				throw new Exception("Missing version for the module: '$sModuleId'");
+				//throw new Exception("Missing version for the module: '$sModuleId'");
+				$sModuleVersion  = '1.0.0';
 			}
 	
 			$sModuleAppVersion = $aModuleInfo['itop_version'];
@@ -225,7 +229,7 @@ class RunTimeEnvironment
 		//
 		foreach ($aInstallByModule as $sModuleName => $aModuleDB)
 		{
-				if ($sModuleName == ROOT_MODULE) continue; // Skip the main module
+			if ($sModuleName == ROOT_MODULE) continue; // Skip the main module
 				
 			if (!array_key_exists($sModuleName, $aRes))
 			{
@@ -284,7 +288,7 @@ class RunTimeEnvironment
 		//
 		$oSourceConfig = new Config(APPCONF.$sSourceEnv.'/'.ITOP_CONFIG_FILE);
 		$oSourceEnv = new RunTimeEnvironment($sSourceEnv);
-		$aAvailableModules = $oSourceEnv->AnalyzeInstallation($oSourceConfig, $sSourceDir);
+		$aAvailableModules = $oSourceEnv->AnalyzeInstallation($oSourceConfig, $sSourceDir); //TODO: use an absolute PATH
 
 		// Do load the required modules
 		//
@@ -419,8 +423,19 @@ class RunTimeEnvironment
 		return true;
 	}
 	
-	public function RecordInstallation(Config $oConfig, $aSelectedModules, $sModulesRelativePath)
+	public function RecordInstallation(Config $oConfig, $sDataModelVersion, $aSelectedModules, $sModulesRelativePath)
 	{
+		// Record datamodel version
+		$aData = array(
+			'source_dir' => $oConfig->Get('source_dir'),
+		);
+		$oInstallRec = new ModuleInstallation();
+		$oInstallRec->Set('name', DATAMODEL_MODULE);
+		$oInstallRec->Set('version', $sDataModelVersion);
+		$oInstallRec->Set('comment', json_encode($aData, true));
+		$oInstallRec->Set('parent_id', 0); // root module
+		$iMainItopRecord = $oInstallRec->DBInsertNoReload();
+		
 		// Record main installation
 		$oInstallRec = new ModuleInstallation();
 		$oInstallRec->Set('name', ITOP_APPLICATION);
@@ -429,9 +444,10 @@ class RunTimeEnvironment
 		$oInstallRec->Set('parent_id', 0); // root module
 		$iMainItopRecord = $oInstallRec->DBInsertNoReload();
 	
+		
 		// Record installed modules
 		//
-		$aAvailableModules = $this->AnalyzeInstallation($oConfig, $sModulesRelativePath);
+		$aAvailableModules = $this->AnalyzeInstallation($oConfig, APPROOT.$sModulesRelativePath);
 		foreach($aSelectedModules as $sModuleId)
 		{
 			$aModuleData = $aAvailableModules[$sModuleId];
@@ -471,6 +487,60 @@ class RunTimeEnvironment
 		// Database is created, installation has been tracked into it
 		return true;	
 	}
+	
+	public function GetApplicationVersion(Config $oConfig)
+	{
+		$aResult = false;
+		try
+		{
+			require_once(APPROOT.'/core/cmdbsource.class.inc.php');
+			CMDBSource::Init($oConfig->GetDBHost(), $oConfig->GetDBUser(), $oConfig->GetDBPwd(), $oConfig->GetDBName());
+			$aSelectInstall = CMDBSource::QueryToArray("SELECT * FROM ".$oConfig->GetDBSubname()."priv_module_install");
+		}
+		catch (MySQLException $e)
+		{
+			// No database or erroneous information
+			return false;
+		}
+	
+		// Scan the list of installed modules to get the version of the 'ROOT' module which holds the main application version
+		foreach ($aSelectInstall as $aInstall)
+		{
+			$sModuleVersion = $aInstall['version'];
+			if ($sModuleVersion == '')
+			{
+				// Though the version cannot be empty in iTop 2.0, it used to be possible
+				// therefore we have to put something here or the module will not be considered
+				// as being installed
+				$sModuleVersion = '0.0.0';
+			}
+	
+			if ($aInstall['parent_id'] == 0)
+			{
+				if ($aInstall['name'] == DATAMODEL_MODULE)
+				{
+					$aResult['datamodel_version'] = $sModuleVersion;
+					$aComments = json_decode($aInstall['comment'], true);
+					if (is_array($aComments))
+					{
+						$aResult = array_merge($aResult, $aComments);
+					}
+				}
+				else
+				{
+					$aResult['product_name'] = $aInstall['name'];
+					$aResult['product_version'] = $sModuleVersion;
+				}
+			}
+		}
+		if (!array_key_exists('datamodel_version', $aResult))
+		{
+			// Versions prior to 2.0 did not record the version of the datamodel
+			// so assume that the datamodel version is equal to the application version
+			$aResult['datamodel_version'] = $aResult['product_version'];
+		}
+		return $aResult;	
+	}
 
 	public static function MakeDirSafe($sDir)
 	{
@@ -501,6 +571,3 @@ class RunTimeEnvironment
 		SetupPage::log_ok($sText);
 	}
 } // End of class
-
-
-?>
diff --git a/setup/setuppage.class.inc.php b/setup/setuppage.class.inc.php
index d1fbbd9b8..69b805a21 100644
--- a/setup/setuppage.class.inc.php
+++ b/setup/setuppage.class.inc.php
@@ -304,5 +304,3 @@ h3.clickable.open {
 		}
 	}
 } // End of class
-
-?>
diff --git a/setup/setuputils.class.inc.php b/setup/setuputils.class.inc.php
index a65a49fba..15d93684b 100644
--- a/setup/setuputils.class.inc.php
+++ b/setup/setuputils.class.inc.php
@@ -657,7 +657,7 @@ function DoCheckDBConnection()
 		'db_pwd': $("#db_pwd").val(),
 		'db_name': $("#db_name").val()
 	}
-	if (oXHRCheckDB !== null)
+	if ((oXHRCheckDB != null) && (oXHRCheckDB != undefined))
 	{
 		oXHRCheckDB.abort();
 		oXHRCheckDB = null;
@@ -937,6 +937,21 @@ EOF
 	{
 		require_once(APPROOT.'/setup/moduleinstaller.class.inc.php');
 		$oConfig = new Config();
+		$sSourceDir = $oWizard->GetParameter('source_dir', '');
+		
+		if (strpos($sSourceDir, APPROOT) !== false)
+		{
+			$sRelativeSourceDir = str_replace(APPROOT, '', $sSourceDir);
+		}
+		else if (strpos($sSourceDir, $oWizard->GetParameter('previous_version_dir')) !== false)
+		{
+			$sRelativeSourceDir = str_replace($oWizard->GetParameter('previous_version_dir'), '', $sSourceDir);
+		}
+		else
+		{
+			throw(new Exception('Internal error: AnalyzeInstallation: source_dir is neither under APPROOT nor under previous_installation_dir ???'));
+		}
+		
 		
 		$aParamValues = array(
 			'db_server' => $oWizard->GetParameter('db_server', ''),
@@ -944,16 +959,43 @@ EOF
 			'db_pwd' => $oWizard->GetParameter('db_pwd', ''),
 			'db_name' => $oWizard->GetParameter('db_name', ''),
 			'db_prefix' => $oWizard->GetParameter('db_prefix', ''),
-			'source_dir' => APPROOT.'datamodel',
+			'source_dir' => $sRelativeSourceDir,
 		);
 		$oConfig->UpdateFromParams($aParamValues, 'datamodel');
+		$aDirsToScan = array($sSourceDir);
 
+		if (is_dir($sSourceDir.'/extensions'))
+		{
+			$aDirsToScan[] = $sSourceDir.'/extensions';
+		}
+		if (is_dir($oWizard->GetParameter('copy_extensions_from')))
+		{
+			$aDirsToScan[] = $oWizard->GetParameter('copy_extensions_from');
+		}
 		$oProductionEnv = new RunTimeEnvironment();
-		$aAvailableModules = $oProductionEnv->AnalyzeInstallation($oConfig, 'datamodel');
+		$aAvailableModules = $oProductionEnv->AnalyzeInstallation($oConfig, $aDirsToScan);
 
 		return $aAvailableModules;
 	}
 
+	public static function GetApplicationVersion($oWizard)
+	{
+		require_once(APPROOT.'/setup/moduleinstaller.class.inc.php');
+		$oConfig = new Config();
+		
+		$aParamValues = array(
+			'db_server' => $oWizard->GetParameter('db_server', ''),
+			'db_user' => $oWizard->GetParameter('db_user', ''),
+			'db_pwd' => $oWizard->GetParameter('db_pwd', ''),
+			'db_name' => $oWizard->GetParameter('db_name', ''),
+			'db_prefix' => $oWizard->GetParameter('db_prefix', ''),
+			'source_dir' => '',
+		);
+		$oConfig->UpdateFromParams($aParamValues, 'datamodel');
+
+		$oProductionEnv = new RunTimeEnvironment();
+		return $oProductionEnv->GetApplicationVersion($oConfig);
+	}
 	/**
 	 * Checks if the content of a directory matches the given manifest
 	 * @param string $sBaseDir Path to the root directory of iTop
@@ -964,6 +1006,7 @@ EOF
 	 */
 	public static function CheckDirAgainstManifest($sBaseDir, $sSourceDir, $aManifest, $aExcludeNames = array('.svn'), $aResult = null)
 	{
+//echo "CheckDirAgainstManifest($sBaseDir, $sSourceDir ...)\n"; 
 		if ($aResult === null)
 		{
 			$aResult = array('added' => array(), 'removed' => array(), 'modified' => array());
@@ -990,10 +1033,13 @@ EOF
 			}
 		}
 
+//echo "The manifest contains ".count($aDirManifest)." files for the directory '$sSourceDir' (and below)\n"; 
+		
 		// Read the content of the directory
 		foreach(glob($sBaseDir.'/'.$sSourceDir .'/*') as $sFilePath)
 		{
 			$sFile = basename($sFilePath);
+//echo "Checking $sFile ($sFilePath)\n"; 
 			
 			if (in_array(basename($sFile), $aExcludeNames)) continue;
 						
@@ -1023,6 +1069,7 @@ EOF
 						if ($sMD5 != $aDirManifest[$sFile]['md5'])
 						{
 							$aResult['modified'][$sSourceDir.'/'.$sFile] = 'Content modified (MD5 checksums differ).';
+//echo $sSourceDir.'/'.$sFile." modified ($sMD5 == {$aDirManifest[$sFile]['md5']})\n";
 						}
 //else
 //{
@@ -1051,9 +1098,10 @@ EOF
 			$aManifest[] = array('path' => (string)$oFileInfo->path, 'size' => (int)$oFileInfo->size, 'md5' => (string)$oFileInfo->md5);
 		}
 		
+		$sBaseDir = preg_replace('|modules/?$|', '', $sBaseDir);
 		$aResults = self::CheckDirAgainstManifest($sBaseDir, 'modules', $aManifest);
 		
-//		echo "<pre>Comparison of ".dirname($sBaseDir)."/modules:\n".print_r($aResults, true)."</pre>";
+//		echo "<pre>Comparison of ".dirname($sBaseDir)."/modules against $sManifestFile:\n".print_r($aResults, true)."</pre>";
 		return $aResults;
 	}
 	
@@ -1084,7 +1132,7 @@ EOF
 		$aResults = array('added' => array(), 'removed' => array(), 'modified' => array());
 		foreach(array('addons', 'core', 'dictionaries', 'js', 'application', 'css', 'pages', 'synchro', 'webservices') as $sDir)
 		{
-			$aTmp = self::CheckDirAgainstManifest($sBaseDir, 'portal', $aManifest);
+			$aTmp = self::CheckDirAgainstManifest($sBaseDir, $sDir, $aManifest);
 			$aResults['added'] = array_merge($aResults['added'], $aTmp['added']);
 			$aResults['modified'] = array_merge($aResults['modified'], $aTmp['modified']);
 			$aResults['removed'] = array_merge($aResults['removed'], $aTmp['removed']);
@@ -1094,4 +1142,99 @@ EOF
 		return $aResults;
 	}
 	
+	public static function CheckVersion($sInstalledVersion, $sSourceDir)
+	{
+		$sManifestFilePath = self::GetVersionManifest($sInstalledVersion);
+		if ($sSourceDir != '')
+		{
+			if (file_exists($sManifestFilePath))
+			{
+				$aDMchanges = self::CheckDataModelFiles($sManifestFilePath, $sSourceDir);
+				//$aPortalChanges = self::CheckPortalFiles($sManifestFilePath, $sSourceDir);
+				//$aCodeChanges = self::CheckApplicationFiles($sManifestFilePath, $sSourceDir);
+				
+				//echo("Changes detected compared to $sInstalledVersion:<br/>DataModel:<br/><pre>".print_r($aDMchanges, true)."</pre>");
+				//echo("Changes detected compared to $sInstalledVersion:<br/>DataModel:<br/><pre>".print_r($aDMchanges, true)."</pre><br/>Portal:<br/><pre>".print_r($aPortalChanges, true)."</pre><br/>Code:<br/><pre>".print_r($aCodeChanges, true)."</pre>");
+				return $aDMchanges;
+			}
+			else
+			{
+				return false;
+			}
+		}
+		else
+		{
+				throw(new Exception("Cannot check version '$sInstalledVersion', no source directory provided to check the files."));
+		}
+	}
+	
+	public static function GetVersionManifest($sInstalledVersion)
+	{
+		if (preg_match('/^([0-9]+)\./', $sInstalledVersion, $aMatches))
+		{
+			return APPROOT.'datamodels/'.$aMatches[1].'.x/manifest-'.$sInstalledVersion.'.xml';
+		}
+		return false;
+	}
+	
+	public static function CheckWritableDirs($aWritableDirs)
+	{
+		$aNonWritableDirs = array();
+		foreach($aWritableDirs as $sDir)
+		{
+			$sFullPath = APPROOT.$sDir;
+			if (is_dir($sFullPath) && !is_writable($sFullPath))
+			{
+				$aNonWritableDirs[APPROOT.$sDir] = new CheckResult(CheckResult::ERROR, "The directory '".APPROOT.$sDir."' exists but is not writable for the application.");
+			}
+			else if (file_exists($sFullPath) && !is_dir($sFullPath))
+			{
+				$aNonWritableDirs[APPROOT.$sDir] = new CheckResult(CheckResult::ERROR, "A file with the same name as '".APPROOT.$sDir."' exists.");
+			}
+			else if (!is_dir($sFullPath) && !is_writable(APPROOT))
+			{
+				$aNonWritableDirs[APPROOT] = new CheckResult(CheckResult::ERROR, "The directory '".APPROOT."' is not writable, the application cannot create the directory '$sDir' inside it.");
+			}				
+		}
+		return $aNonWritableDirs;		
+	}
+	
+	public static function GetLatestDataModelDir()
+	{
+		$sBaseDir = APPROOT.'datamodels';
+		
+		$aDirs = glob($sBaseDir.'/*', GLOB_MARK | GLOB_ONLYDIR);
+		if ($aDirs !== false)
+		{
+			sort($aDirs);
+			
+			return array_pop($aDirs);
+		}
+		return false;
+	}
+	
+	public static function GetCompatibleDataModelDir($sInstalledVersion)
+	{
+		if (preg_match('/^([0-9]+)\./', $sInstalledVersion, $aMatches))
+		{
+			$sMajorVersion = $aMatches[1];
+			$sDir = APPROOT.'datamodels/'.$sMajorVersion.'.x/';
+			if (is_dir($sDir))
+			{
+				return $sDir;
+			}
+		}
+		return false;
+	}
+	
+	static public function GetDataModelVersion($sDatamodelDir)
+	{
+		$sVersionFile = $sDatamodelDir.'version.xml';
+		if (file_exists($sVersionFile))
+		{
+			$oParams = new XMLParameters($sVersionFile);
+			return $oParams->Get('version');
+		}
+		return false;
+	}
 }
\ No newline at end of file
diff --git a/setup/wizardcontroller.class.inc.php b/setup/wizardcontroller.class.inc.php
index c6603b0f2..276704dee 100644
--- a/setup/wizardcontroller.class.inc.php
+++ b/setup/wizardcontroller.class.inc.php
@@ -164,6 +164,23 @@ class WizardController
 	protected function DisplayStep(WizardStep $oStep)
 	{
 		$oPage = new SetupPage($oStep->GetTitle());
+		if ($oStep->RequiresWritableConfig())
+		{
+			$sConfigFile = utils::GetConfigFilePath();
+			if (file_exists($sConfigFile))
+			{
+				// The configuration file already exists
+				if (!is_writable($sConfigFile))
+				{
+					$oP = new SetupPage('Installation Cannot Continue');
+					$oP->add("<h2>Fatal error</h2>\n");
+					$oP->error("<b>Error:</b> the configuration file '".$sConfigFile."' already exists and cannot be overwritten.");
+					$oP->p("The wizard cannot modify the configuration file for you. If you want to upgrade ".ITOP_APPLICATION.", make sure that the file '<b>".realpath($sConfigFile)."</b>' can be modified by the web server.");
+					$oP->output();
+					return;
+				}
+			}			
+		}
 		$oPage->add_linked_script('../setup/setup.js');
 		$oPage->add_script("function CanMoveForward()\n{\n".$oStep->JSCanMoveForward()."\n}\n");
 		$oPage->add_script("function CanMoveBackward()\n{\n".$oStep->JSCanMoveBackward()."\n}\n");
@@ -432,6 +449,15 @@ abstract class WizardStep
 		return 'return true;';
 	}
 
+	/**
+	 * Tells whether this step of the wizard requires that the configuration file be writable
+	 * @return bool True if the wizard will possibly need to modify the configuration at some point
+	 */
+	public function RequiresWritableConfig()
+	{
+		return true;
+	}
+
 	/**
 	 * Overload this function to implement asynchronous action(s) (AJAX)
 	 * @param string $sCode The code of the action (if several actions need to be distinguished)
diff --git a/setup/wizardsteps.class.inc.php b/setup/wizardsteps.class.inc.php
index 157c4f985..bee0213dc 100644
--- a/setup/wizardsteps.class.inc.php
+++ b/setup/wizardsteps.class.inc.php
@@ -157,7 +157,7 @@ class WizStepInstallOrUpgrade extends WizardStep
 		$sNextStep = '';
 		$sInstallMode = utils::ReadParam('install_mode');
 
-		$this->oWizard->SaveParameter('source_dir', '');
+		$this->oWizard->SaveParameter('previous_version_dir', '');
 		$this->oWizard->SaveParameter('db_server', '');
 		$this->oWizard->SaveParameter('db_user', '');
 		$this->oWizard->SaveParameter('db_pwd', '');
@@ -169,6 +169,9 @@ class WizStepInstallOrUpgrade extends WizardStep
 		if ($sInstallMode == 'install')
 		{
 			$this->oWizard->SetParameter('install_mode', 'install');
+			$sFullSourceDir = SetupUtils::GetLatestDataModelDir();
+			$this->oWizard->SetParameter('source_dir', $sFullSourceDir);
+			$this->oWizard->SetParameter('datamodel_version', SetupUtils::GetDataModelVersion($sFullSourceDir));
 			$sNextStep = 'WizStepLicense';
 		}
 		else
@@ -183,7 +186,6 @@ class WizStepInstallOrUpgrade extends WizardStep
 	public function Display(WebPage $oPage)
 	{
 		$sInstallMode = $this->oWizard->GetParameter('install_mode', '');
-		$sSourceDir = $this->oWizard->GetParameter('source_dir', '');
 		$sDBServer = $this->oWizard->GetParameter('db_server', '');
 		$sDBUser = $this->oWizard->GetParameter('db_user', '');
 		$sDBPwd = $this->oWizard->GetParameter('db_pwd', '');
@@ -191,6 +193,7 @@ class WizStepInstallOrUpgrade extends WizardStep
 		$sDBPrefix = $this->oWizard->GetParameter('db_prefix', '');
 		$bDBBackup = $this->oWizard->GetParameter('db_backup', false);
 		$sDBBackupPath = $this->oWizard->GetParameter('db_backup_path', '');
+		$sPreviousVersionDir = '';
 		if ($sInstallMode == '')
 		{
 			$sDBBackupPath = APPROOT.'data/'.ITOP_APPLICATION.strftime('-backup-%Y-%m-%d.zip');
@@ -205,14 +208,15 @@ class WizStepInstallOrUpgrade extends WizardStep
 				$sDBPwd = $aPreviousInstance['db_pwd'];
 				$sDBName = $aPreviousInstance['db_name'];
 				$sDBPrefix = $aPreviousInstance['db_prefix'];
-				//TODO: check if we can run the backup
 				$sStyle = '';
+				$sPreviousVersionDir = APPROOT;
 			}
 			else
 			{
 				$sInstallMode = 'install';
 			}
 		}
+		$sPreviousVersionDir = $this->oWizard->GetParameter('previous_version_dir', $sPreviousVersionDir);
 		
 		$sUpgradeInfoStyle = '';
 		if ($sInstallMode == 'install')
@@ -227,7 +231,7 @@ class WizStepInstallOrUpgrade extends WizardStep
 		//$oPage->add('<fieldset  id="upgrade_info"'.$sUpgradeInfoStyle.'>');
 		//$oPage->add('<legend>Information about the previous instance:</legend>');
 		$oPage->add('<table id="upgrade_info"'.$sUpgradeInfoStyle.'>');
-		$oPage->add('<tr><td>Location on the disk:</td><td><input id="source_dir" type="text" name="source_dir" value="'.htmlentities($sSourceDir, ENT_QUOTES, 'UTF-8').'" size="25"/></td></tr>');
+		$oPage->add('<tr><td>Location on the disk:</td><td><input id="previous_version_dir" type="text" name="previous_version_dir" value="'.htmlentities($sPreviousVersionDir, ENT_QUOTES, 'UTF-8').'" size="25"/></td></tr>');
 		SetupUtils::DisplayDBParameters($oPage, false, $sDBServer, $sDBUser, $sDBPwd, $sDBName, $sDBPrefix);
 
 		$aBackupChecks = SetupUtils::CheckBackupPrerequisites($sDBBackupPath);
@@ -263,7 +267,7 @@ class WizStepInstallOrUpgrade extends WizardStep
 <<<EOF
 	$("#radio_update").bind('change', function() { if (this.checked ) { $('#upgrade_info').show(); WizardUpdateButtons(); } else { $('#upgrade_info').hide(); } });
 	$("#radio_install").bind('change', function() { if (this.checked ) { $('#upgrade_info').hide(); WizardUpdateButtons(); } else { $('#upgrade_info').show(); } });
-	$("#source_dir").bind('change keyup', function() { WizardAsyncAction('check_path', { source_dir: $('#source_dir').val() }); });
+	$("#previous_version_dir").bind('change keyup', function() { WizardAsyncAction('check_path', { previous_version_dir: $('#previous_version_dir').val() }); });
 	$("#db_backup_path").bind('change keyup', function() { WizardAsyncAction('check_backup', { db_backup_path: $('#db_backup_path').val() }); });
 EOF
 		);
@@ -274,8 +278,8 @@ EOF
 		switch($sCode)
 		{
 			case 'check_path':
-			$sSourceDir = $aParameters['source_dir'];
-			$aPreviousInstance = SetupUtils::GetPreviousInstance($sSourceDir);
+			$sPreviousVersionDir = $aParameters['previous_version_dir'];
+			$aPreviousInstance = SetupUtils::GetPreviousInstance($sPreviousVersionDir);
 			if ($aPreviousInstance['found'])
 			{
 				$sDBServer = htmlentities($aPreviousInstance['db_server'], ENT_QUOTES, 'UTF-8');
@@ -358,90 +362,8 @@ EOF
  */
 class WizStepDetectedInfo extends WizardStep
 {
-	public function GetTitle()
-	{
-		return 'Detected Info';
-	}
+	protected $bCanMoveForward;
 	
-	public function GetPossibleSteps()
-	{
-		return array('WizStepUpgradeKeep', 'WizStepUpgradeAuto', 'WizStepLicense2');
-	}
-	
-	public function ProcessParams($bMoveForward = true)
-	{
-
-		return array('class' => 'WizStepLicense2', 'state' => '');
-	}
-	
-	public function Display(WebPage $oPage)
-	{
-		$oPage->p('Info about the detected version');
-		$sSourceDir = $this->oWizard->GetParameter('source_dir', '');
-		$aInstalledModules = SetupUtils::AnalyzeInstallation($this->oWizard);		
-		$sVersion = $aInstalledModules[ROOT_MODULE]['version_db'];
-		
-		if (preg_match('/^([0-9]+)\.([0-9]+)\.([0-9]+)\.(.*)$/', $sVersion, $aMatches))
-		{
-			$sVersion = $aMatches[1].'.'.$aMatches[2].'.'.$aMatches[3];
-		}
-		
-		$sKnownManifestFile = APPROOT.'setup/known-versions/'.$sVersion.'/manifest.xml';
-		if ($sSourceDir != '')
-		{
-			if (file_exists($sKnownManifestFile))
-			{
-				$aDMchanges = SetupUtils::CheckDataModelFiles($sKnownManifestFile, $sSourceDir);
-				$aPortalChanges = SetupUtils::CheckPortalFiles($sKnownManifestFile, $sSourceDir);
-				$aCodeChanges = SetupUtils::CheckApplicationFiles($sKnownManifestFile, $sSourceDir);
-				
-				$oPage->add("Changes detected compared to $sVersion:<br/>DataModel:<br/><pre>".print_r($aDMchanges, true)."</pre><br/>Portal:<br/><pre>".print_r($aPortalChanges, true)."</pre><br/>Code:<br/><pre>".print_r($aCodeChanges, true)."</pre>");
-			}
-			else
-			{
-				$oPage->p("Unknown version $sVersion. Do you want to upgrade anyway ??? NOT GUARANTEED AT ALL !!!");
-			}
-		}
-		else
-		{
-			$oPage->p("No source dir provided assuming that the installed version '$sVersion' is genuine iTop build...");
-		}
-		
-	}
-}
-
-/**
- * Keep or Upgrade choice
- */
-class WizStepUpgradeKeep extends WizardStep
-{
-	public function GetTitle()
-	{
-		return 'Keep or Upgrade';
-	}
-	
-	public function GetPossibleSteps()
-	{
-		return array('WizStepModulesChoice');
-	}
-	
-	public function ProcessParams($bMoveForward = true)
-	{
-
-		return array('class' => 'WizStepModulesChoice', 'state' => 'start_upgrade');
-	}
-	
-	public function Display(WebPage $oPage)
-	{
-		$oPage->p('Keep or Upgrade the data model');
-	}
-}
-
-/**
- * Automatic Upgrade info
- */
-class WizStepUpgradeAuto extends WizardStep
-{
 	public function GetTitle()
 	{
 		return 'Upgrade Information';
@@ -449,20 +371,261 @@ class WizStepUpgradeAuto extends WizardStep
 	
 	public function GetPossibleSteps()
 	{
-		return array('WizStepModulesChoice');
+		return array('WizStepUpgradeMiscParams', 'WizStepLicense2');
 	}
 	
 	public function ProcessParams($bMoveForward = true)
 	{
+		$sUpgradeType = utils::ReadParam('upgrade_type');
+		
+		$this->oWizard->SetParameter('mode', 'upgrade');
+		$this->oWizard->SetParameter('upgrade_type', $sUpgradeType);
+		$this->oWizard->SaveParameter('copy_extensions_from', '');
+		$bDisplayLicense = $this->oWizard->GetParameter('display_license');
 
-		return array('class' => 'WizStepModulesChoice', 'state' => 'start_upgrade');
+		switch ($sUpgradeType)
+		{
+			case 'keep-previous':
+			$sSourceDir = utils::ReadParam('relative_source_dir', '', false, 'raw_data');
+			$this->oWizard->SetParameter('source_dir', $this->oWizard->GetParameter('previous_version_dir').'/'.$sSourceDir);
+			$this->oWizard->SetParameter('datamodel_version', utils::ReadParam('datamodel_previous_version', '', false, 'raw_data'));
+			break;
+			
+			case 'use-compatible':
+			$sDataModelPath = utils::ReadParam('datamodel_path', '', false, 'raw_data');
+			$this->oWizard->SetParameter('source_dir', $sDataModelPath);
+			$this->oWizard->SaveParameter('datamodel_version', '');
+			break;
+			
+			default:
+			// Do nothing, maybe the user pressed the Back button
+		}
+		if ($bDisplayLicense)
+		{
+			$aRet = array('class' => 'WizStepLicense2', 'state' => '');
+		}
+		else
+		{
+			$aRet = array('class' => 'WizStepUpgradeMiscParams', 'state' => '');
+		}
+		return $aRet;
 	}
 	
 	public function Display(WebPage $oPage)
 	{
-		$oPage->p('Automatic Upgrade information');
+		$oPage->add_style(
+<<<EOF
+#changes_summary {
+	max-height: 200px;
+	overflow: auto;
+}
+#changes_summary div {
+	width:100;
+	margin-top:0;
+	padding-top: 0.5em;
+	padding-left: 0;
+}
+#changes_summary div ul {
+	margin-left:0;
+	padding-left: 20px;
+}
+#changes_summary div.closed ul {
+	display:none;
+}
+#changes_summary div li {
+	list-style: none;
+	width: 100;
+	margin-left:0;
+	padding-left: 0em;
+}
+.title {
+	padding-left: 20px;
+	font-weight: bold;
+	cursor: pointer;
+	background: url(../images/minus.gif) 2px 2px no-repeat;
+}
+#changes_summary div.closed .title {
+	background: url(../images/plus.gif) 2px 2px no-repeat;
+}
+EOF
+		);		
+		$this->bCanMoveForward = true;
+		$bDisplayLicense = true;
+		$sPreviousVersionDir = $this->oWizard->GetParameter('previous_version_dir', '');
+		$aInstalledInfo = SetupUtils::GetApplicationVersion($this->oWizard);
+				
+		if ($aInstalledInfo === false)
+		{
+			throw(new Exception('No previous version of '.ITOP_APPLICATION.' found in the supplied database. The upgrade cannot continue.'));
+		}
+		else if (strcasecmp($aInstalledInfo['product_name'], ITOP_APPLICATION) != 0)
+		{
+			$oPage->p("<b>Warning: The installed products seem different. Are you sure the you want to upgrade {$aInstalledInfo['product_name']} with ".ITOP_APPLICATION."?</b>");			
+		}
+		
+		$sInstalledVersion = $aInstalledInfo['product_version'];
+		$sInstalledDataModelVersion = $aInstalledInfo['datamodel_version'];
+		
+		if ($sInstalledDataModelVersion == '$ITOP_VERSION$.$WCREV$')
+		{
+			// Special case for upgrading some  development versions (temporary)
+			$sLatestDMDir = SetupUtils::GetLatestDataModelDir();
+			$sInstalledDataModelVersion = SetupUtils::GetDataModelVersion($sLatestDMDir);
+		}
+		
+		$oPage->add("<h2>Information about the upgrade from version $sInstalledVersion to ".ITOP_VERSION.'.'.ITOP_REVISION."</h2>");
+		
+		if ($sInstalledVersion == (ITOP_VERSION.'.'.ITOP_REVISION))
+		{
+			// Reinstalling the same version let's skip the license agreement...
+			$bDisplayLicense = false;
+		}		
+		$this->oWizard->SetParameter('license', $bDisplayLicense); // Remember for later
+		
+			$sCompatibleDMDir = SetupUtils::GetCompatibleDataModelDir($sInstalledDataModelVersion);
+		if ($sCompatibleDMDir === false)
+		{
+			// No compatible version exists... cannot upgrade. Either it is too old, or too new (downgrade !)
+			$this->bCanMoveForward = false;
+			$oPage->p("The current version of ".ITOP_APPLICATION." (".ITOP_VERSION.'.'.ITOP_REVISION.") does not sem to be compatible with the installed version ($sInstalledVersion).");
+			$oPage->p("The upgrade cannot continue, sorry.");
+		}
+		else
+		{
+			$sUpgradeDMVersion = SetupUtils::GetDataModelVersion($sCompatibleDMDir);
+			$sPreviousSourceDir = isset($aInstalledInfo['source_dir']) ? $aInstalledInfo['source_dir'] : 'modules';
+			$aChanges = false;
+			if (is_dir($sPreviousVersionDir))
+			{
+				// Check if the previous version is a "genuine" one or not...
+				$aChanges = SetupUtils::CheckVersion($sInstalledDataModelVersion, $sPreviousVersionDir.'/'.$sPreviousSourceDir);
+			}
+			if (($aChanges !== false) && (count($aChanges) > 0))
+			{
+				// Some changes were detected, prompt the user to keep or discard them
+				$oPage->p("<img src=\"../images/error.png\"/>&nbsp;Some modifications were detected between the ".ITOP_APPLICATION." version in '$sPreviousVersionDir' and a genuine $sInstalledVersion version.");
+				$oPage->p("What do you want to do?");
+
+				$aWritableDirs = array('modules', 'portal');
+				$aErrors = SetupUtils::CheckWritableDirs($aWritableDirs);
+				$sChecked = ($this->oWizard->GetParameter('upgrade_type') == 'keep-previous') ? ' checked ' : '';
+				$sDisabled = (count($aErrors) > 0) ? ' disabled ' : '';
+				
+				$oPage->p('<input id="radio_upgrade_keep" type="radio" name="upgrade_type" value="keep-previous"'.$sChecked.$sDisabled.'/><label for="radio_upgrade_keep">&nbsp;Preserve the modifications of the installed version (the dasboards inside '.ITOP_APPLICATION.' may not be editable).</label>');
+				$oPage->add('<input type="hidden" name="datamodel_previous_version" value="'.htmlentities($sInstalledDataModelVersion, ENT_QUOTES, 'UTF-8').'">');
+				
+				$oPage->add('<input type="hidden" name="relative_source_dir" value="'.htmlentities($sPreviousSourceDir, ENT_QUOTES, 'UTF-8').'">');
+				
+				if (count($aErrors) > 0)
+				{
+					$oPage->p("Cannot copy the installed version due to the following access rights issue(s):");
+					foreach($aErrors as $sDir => $oCheckResult)
+					{
+						$oPage->p('<img src="../images/error.png"/>&nbsp;'.$oCheckResult->sLabel);
+					}
+				}
+						
+				$sChecked = ($this->oWizard->GetParameter('upgrade_type') == 'use-compatible') ? ' checked ' : '';
+				
+				$oPage->p('<input id="radio_upgrade_convert" type="radio" name="upgrade_type" value="use-compatible"'.$sChecked.'/><label for="radio_upgrade_convert">&nbsp;Discard the modifications, use a standard '.$sUpgradeDMVersion.' data model.</label>');
+				
+				$oPage->add('<input type="hidden" name="datamodel_path" value="'.htmlentities($sCompatibleDMDir, ENT_QUOTES, 'UTF-8').'">');
+				$oPage->add('<input type="hidden" name="datamodel_version" value="'.htmlentities($sUpgradeDMVersion, ENT_QUOTES, 'UTF-8').'">');
+				
+				$oPage->add('<div id="changes_summary"><div class="closed"><span class="title">Details of the modifications</span><div>');
+				if (count($aChanges['added']) > 0)
+				{
+					$oPage->add('<ul>New files added:');
+					foreach($aChanges['added'] as $sFilePath => $void)
+					{
+						$oPage->add('<li>'.$sFilePath.'</li>');
+					}
+					$oPage->add('</ul>');
+				}
+				if (count($aChanges['removed']) > 0)
+				{
+					$oPage->add('<ul>Deleted files:');
+					foreach($aChanges['removed'] as $sFilePath => $void)
+					{
+						$oPage->add('<li>'.$sFilePath.'</li>');
+					}
+					$oPage->add('</ul>');
+				}
+				if (count($aChanges['modified']) > 0)
+				{
+					$oPage->add('<ul>Modified files:');
+					foreach($aChanges['modified'] as $sFilePath => $void)
+					{
+						$oPage->add('<li>'.$sFilePath.'</li>');
+					}
+					$oPage->add('</ul>');
+				}
+				$oPage->add('</div></div></div>');
+			}
+			else
+			{
+				// No changes detected... or no way to tell because of the lack of a manifest or previous source dir
+				// Use the "compatible" datamodel as-is.
+				$oPage->p("<img src=\"../images/validation_ok.png\"/>&nbsp;The datamodel will be upgraded from version $sInstalledDataModelVersion to version $sUpgradeDMVersion.");
+				$oPage->add('<input type="hidden" name="upgrade_type" value="use-compatible">');
+				$oPage->add('<input type="hidden" name="datamodel_path" value="'.htmlentities($sCompatibleDMDir, ENT_QUOTES, 'UTF-8').'">');
+				$oPage->add('<input type="hidden" name="datamodel_version" value="'.htmlentities($sUpgradeDMVersion, ENT_QUOTES, 'UTF-8').'">');
+			}
+
+			// Check if there are "extensions" to preserve and if it's possible
+			if (is_dir($sPreviousVersionDir.'/extensions'))
+			{
+				$aExtensions = glob($sPreviousVersionDir.'/extensions/*', GLOB_ONLYDIR);
+				if (($aExtensions !== false) && (count($aExtensions)>0))
+				{
+					$aWritableDirs = array('extensions');
+					$aErrors = SetupUtils::CheckWritableDirs($aWritableDirs);
+					if (count($aErrors) > 0)
+					{
+						$oPage->p("Cannot copy the extensions from '$sPreviousVersionDir/extensions' to '".APPROOT."extensions' due to the following access rights issue(s):");
+						foreach($aErrors as $sDir => $oCheckResult)
+						{
+							$oPage->p('<img src="../images/error.png"/>&nbsp;'.$oCheckResult->sLabel);
+						}
+					}
+					else
+					{
+						$oPage->p("<b>Note:</b> The extensions present in '$sPreviousVersionDir/extensions' will be copied to '".APPROOT."extensions'.");
+						$oPage->add('<input type="hidden" name="copy_extensions_from" value="'.htmlentities($sPreviousVersionDir.'/extensions', ENT_QUOTES, 'UTF-8').'">');
+					}
+				}
+			}			
+			$oPage->add_ready_script(
+<<<EOF
+	$("#changes_summary .title").click(function() { $(this).parent().toggleClass('closed'); } );
+	$('input[name=upgrade_type]').bind('click change', function() { WizardUpdateButtons(); });
+EOF
+			);	
+		}				
+	}
+	
+	public function CanMoveForward()
+	{
+		return $this->bCanMoveForward;
+	}
+	
+	/**
+	 * Tells whether the "Next" button should be enabled interactively
+	 * @return string A piece of javascript code returning either true or false
+	 */
+	public function JSCanMoveForward()
+	{
+		return
+<<<EOF
+	if ($("#radio_upgrade_keep").length == 0) return true;
+	
+	bRet = ($('input[name=upgrade_type]:checked').length > 0);
+	return bRet;
+EOF
+		;
 	}
 }
+
 /**
  * License acceptation screen
  */
@@ -534,12 +697,12 @@ class WizStepLicense2 extends WizStepLicense
 {
 	public function GetPossibleSteps()
 	{
-		return array('WizStepUpgradeKeep', 'WizStepUpgradeAuto');
+		return array('WizStepUpgradeMiscParams');
 	}
 	
 	public function ProcessParams($bMoveForward = true)
 	{
-		return array('class' => 'WizStepUpgradeAuto', 'state' => '');
+		return array('class' => 'WizStepUpgradeMiscParams', 'state' => '');
 	}
 }
 
@@ -799,6 +962,67 @@ EOF
 	}
 }
 
+/**
+ * Miscellaneous Parameters (URL...) in case of upgrade
+ */
+class WizStepUpgradeMiscParams extends WizardStep
+{
+	public function GetTitle()
+	{
+		return 'Miscellaneous Parameters';
+	}
+	
+	public function GetPossibleSteps()
+	{
+		return array('WizStepModulesChoice');
+	}
+	
+	public function ProcessParams($bMoveForward = true)
+	{
+		$this->oWizard->SaveParameter('application_url', '');
+		return array('class' => 'WizStepModulesChoice', 'state' => 'start_upgrade');
+	}
+	
+	public function Display(WebPage $oPage)
+	{
+		$sApplicationURL = $this->oWizard->GetParameter('application_url', utils::GetDefaultUrlAppRoot());
+		$oPage->add('<h2>Additional parameters</h2>');
+		$oPage->add('<fieldset>');
+		$oPage->add('<legend>Application URL</legend>');
+		$oPage->add('<table>');
+		$oPage->add('<tr><td>URL: </td><td><input id="application_url" name="application_url" type="text" size="35" maxlength="1024" value="'.htmlentities($sApplicationURL, ENT_QUOTES, 'UTF-8').'"><span id="v_application_url"/></td><tr>');
+		$oPage->add('<tr><td colspan="2">Change the value above if the end-users will be accessing the application by another path due to a specific configuration of the web server.</td><tr>');
+		$oPage->add('</table>');
+		$oPage->add('</fieldset>');
+		$oPage->add_ready_script(
+<<<EOF
+		$('#application_url').bind('change keyup', function() { WizardUpdateButtons(); } );
+EOF
+		);
+	}
+	
+	/**
+	 * Tells whether the "Next" button should be enabled interactively
+	 * @return string A piece of javascript code returning either true or false
+	 */
+	public function JSCanMoveForward()
+	{
+		return
+<<<EOF
+	bRet = ($('#application_url').val() != '');
+	if (!bRet)
+	{
+		$("#v_application_url").html('<img src="../images/validation_error.png" title="This field cannot be empty"/>');
+	}
+	else
+	{
+		$("#v_application_url").html('');
+	}
+	return bRet;
+EOF
+		;
+	}
+}
 /**
  * Choice of the modules to be installed
  */
@@ -848,6 +1072,10 @@ class WizStepModulesChoice extends WizardStep
 					$sDisplayChoices .= $this->GetSelectedModules($aStepInfo, $aSelectedChoices[$i], $aModules);
 				}
 				$sDisplayChoices .= '</ul>';
+				if (class_exists('CreateITILProfilesInstaller'))
+				{
+					$this->oWizard->SetParameter('old_addon', true);
+				}
 				$this->oWizard->SetParameter('selected_modules', json_encode(array_keys($aModules)));
 				$this->oWizard->SetParameter('display_choices', $sDisplayChoices);
 				return array('class' => 'WizStepSummary', 'state' => '');
@@ -865,6 +1093,7 @@ class WizStepModulesChoice extends WizardStep
 	{
 		$aStepInfo = $this->GetStepInfo();
 		$oPage->add_style("div.choice { margin: 0.5em;}");
+		$oPage->add_style("div.choice a { text-decoration:none; font-weight: bold; color: #1C94C4 }");
 		$oPage->add_style("div.description { margin-left: 2em; }");
 		$oPage->add_style(".choice-disabled { color: #999; }");
 		$oPage->add('<table><tr>');
@@ -891,7 +1120,8 @@ class WizStepModulesChoice extends WizardStep
 		
 		// Build the default choices
 		$aDefaults = array();
-		$this->GetDefaults($aStepInfo, $aDefaults);
+		$aModules = SetupUtils::AnalyzeInstallation($this->oWizard);
+		$this->GetDefaults($aStepInfo, $aDefaults, $aModules);
 		$index = $this->GetStepIndex();
 		
 		// retrieve the saved selection
@@ -903,7 +1133,7 @@ class WizStepModulesChoice extends WizardStep
 		}
 		$aSelectedComponents = $aParameters[$index];
 
-		$oPage->add('<div style="max-height:250px;overflow:auto;border:#ccc 1px solid;">');
+		$oPage->add('<div style="height:250px;overflow:auto;border:#ccc 1px solid;">');
 		$this->DisplayOptions($oPage, $aStepInfo, $aSelectedComponents);
 		$oPage->add('</div>');
 		
@@ -964,7 +1194,7 @@ EOF
 		);
 	}
 	
-	protected function GetDefaults($aInfo, &$aDefaults, $sParentId = '')
+	protected function GetDefaults($aInfo, &$aDefaults, $aModules, $sParentId = '')
 	{
 		$aOptions = isset($aInfo['options']) ? $aInfo['options'] : array();
 		foreach($aOptions as $index => $aChoice)
@@ -974,6 +1204,15 @@ EOF
 			{
 				$aDefaults[$sChoiceId] = $sChoiceId;
 			}
+			foreach($aChoice['modules'] as $sModuleId)
+			{
+				if ($aModules[$sModuleId]['version_db'] != '')
+				{
+					// A module corresponding to this choice is installed, the whole choice is selected
+					$aDefaults[$sChoiceId] = $sChoiceId;
+					break;
+				}
+			}
 			if (isset($aChoice['sub_options']))
 			{
 				$this->GetDefaults($aChoice['sub_options'], $aDefaults, $sChoiceId);
@@ -996,10 +1235,30 @@ EOF
 			}
 			if (isset($aChoice['sub_options']))
 			{
-				$this->GetDefaults($aChoice['sub_options'], $aDefaults, $sChoiceId);
+				$this->GetDefaults($aChoice['sub_options'], $aDefaults, $aModules, $sChoiceId);
 			}
 			$index++;
 		}
+		
+		// the installed choices have precedence over the 'default' choices
+		$sChoiceName = null;
+		foreach($aAlternatives as $index => $aChoice)
+		{
+			$sChoiceId = $sParentId.'_'.$index;
+			if ($sChoiceName == null)
+			{
+				$sChoiceName = $sChoiceId;
+			}
+			foreach($aChoice['modules'] as $sModuleId)
+			{
+				if ($aModules[$sModuleId]['version_db'] != '')
+				{
+					// A module corresponding to this choice is installed, the whole choice is selected
+					$aDefaults[$sChoiceName] = $sChoiceId;
+					break;
+				}
+			}
+		}
 	} 
 	
 	/**
@@ -1023,7 +1282,7 @@ EOF
 					{
 						$aModules[$sModuleId] = true;
 					}
-				}				
+				}
 			}
 			
 		}
@@ -1113,65 +1372,102 @@ EOF
 		{
 			$index = $idx;
 		}
+		
+		$aSteps = array();
 		if (@file_exists($this->GetSourceFilePath()))
 		{
 			$aParams = new XMLParameters($this->GetSourceFilePath());
 			$aSteps = $aParams->Get('steps', array());
-			if (array_key_exists($index, $aSteps))
-			{
-				$aStepInfo = $aSteps[$index];
-			}
+			$bAddExtensionsOnly = true;
 		}
-		else if ($idx == 0)
+		else
 		{
 			// No wizard configuration provided, build a standard one:
-			$aAvailableModules = SetupUtils::AnalyzeInstallation($this->oWizard);
-			$aStepInfo = array(
+			$bAddExtensionsOnly = false;
+			$aSteps[] = array(
 				'title' => 'Modules Selection',
 				'description' => '<h2>Select the modules to install. You can launch the installation again to install new modules, but you cannot remove already installed modules.</h2>',
 				'banner' => '/images/modules.png',
-				'options' => array(),
+				'options' => array()
+				);
+		}
+		
+		// Additional step for the extensions
+		$aSteps[] = array(
+			'title' => 'Extensions',
+			'description' => '<h2>Select additional extensions to install. You can launch the installation again to install new extensions, but you cannot remove already installed extensions.</h2>',
+			'banner' => '/images/extension.png',
+			'options' => array()
 			);
-			
-			try
-			{
-				$sDefaultAppPath = 	utils::GetDefaultUrlAppRoot();		
-			}
-			catch(Exception $e)
-			{
-				$sDefaultAppPath = '..';
-			}
 		
-			foreach($aAvailableModules as $sModuleId => $aModule)
+		try
+		{
+			$sDefaultAppPath = 	utils::GetDefaultUrlAppRoot();		
+		}
+		catch(Exception $e)
+		{
+			$sDefaultAppPath = '..';
+		}
+	
+		$aAvailableModules = SetupUtils::AnalyzeInstallation($this->oWizard);
+		foreach($aAvailableModules as $sModuleId => $aModule)
+		{
+			if ($sModuleId == ROOT_MODULE) continue; // Convention: the version number of the application (and datamodel) are stored as a module named ROOT_MODULE
+	
+			$sModuleLabel = $aModule['label'];
+			$sModuleHelp = $aModule['doc.more_information'];
+			$sMoreInfo = (!empty($aModule['doc.more_information'])) ? "<a href=\"$sDefaultAppPath{$aModule['doc.more_information']}\" target=\"_blank\">more info</a>": '';
+			if (($aModule['category'] != 'authentication') && ($aModule['visible']))
 			{
-				if ($sModuleId == ROOT_MODULE) continue; // Convention: the version number of the application is stored as a module named ROOT_MODULE
-		
-				$sModuleLabel = $aModule['label'];
-				$sModuleHelp = $aModule['doc.more_information'];
-				$sMoreInfo = (!empty($aModule['doc.more_information'])) ? "<a href=\"$sDefaultAppPath{$aModule['doc.more_information']}\" target=\"_blank\">more info</a>": '';
-				if (($aModule['category'] != 'authentication') && ($aModule['visible']))
+				if (($bAddExtensionsOnly) && (!$this->IsExtension($aModule))) continue;
+				
+				if ($this->IsExtension($aModule))
 				{
-					$aStepInfo['options'][$index] = array(
-						'title' => $sModuleLabel,
-						'description' => '',
-						'more_info' => $sMoreInfo,
-						'default' => true, // by default offer to install all modules
-						'modules' => array($sModuleId),
-					);
-					
-					switch($aModule['install']['flag'])
-					{
-						case MODULE_ACTION_MANDATORY:
-						$aStepInfo['options'][$index]['mandatory']  = true;
-						break;
-						
-					}
-					$index++;
+					$iStepIndex = count($aSteps) - 1;
 				}
+				else
+				{
+					$iStepIndex = 0;
+				}
+				$aSteps[$iStepIndex]['options'][] = array(
+					'title' => $sModuleLabel,
+					'description' => '',
+					'more_info' => $sMoreInfo,
+					'default' => true, // by default offer to install all modules
+					'modules' => array($sModuleId),
+					'mandatory' => ($aModule['install']['flag'] & MODULE_ACTION_MANDATORY) ? true : false,
+				);
 			}
 		}
+		
+		if (count($aSteps[count($aSteps) - 1]['options']) == 0)
+		{
+			// No extensions at all, remove the last step
+			unset($aSteps[1]);
+		}
+		
+		if (array_key_exists($index, $aSteps))
+		{
+			$aStepInfo = $aSteps[$index];
+		}
+	
 		return $aStepInfo;
 	}
+	
+	protected function GetExtensionsStepInfo()
+	{
+		// let the user select from the list of modules located in the "extensions" folder
+	}
+	
+	protected function IsExtension($aModule)
+	{
+		// root_dir is the directory containing the module, check if its parent is "extensions"
+		if (basename(dirname($aModule['root_dir'])) == 'extensions')
+		{
+			return true;
+		}
+		return false;
+	}
 		
 	protected function DisplayOptions($oPage, $aStepInfo, $aSelectedComponents, $sParentId = '')
 	{
@@ -1222,7 +1518,8 @@ EOF
 	
 	protected function DisplayChoice($oPage, $aChoice, $aSelectedComponents, $sChoiceId)
 	{
-		$oPage->add('<label for="choice'.$sChoiceId.'"><b>'.htmlentities($aChoice['title'], ENT_QUOTES, 'UTF-8').'</b></label>');
+		$sMoreInfo = isset($aChoice['more_info']) ? $aChoice['more_info'] : '';
+		$oPage->add('<label for="choice'.$sChoiceId.'"><b>'.htmlentities($aChoice['title'], ENT_QUOTES, 'UTF-8').'</b></label> '.$sMoreInfo);
 		$sDescription = isset($aChoice['description']) ? htmlentities($aChoice['description'], ENT_QUOTES, 'UTF-8') : '';
 		$oPage->add('<div class="description">'.$sDescription.'<span id="sub_choices'.$sChoiceId.'">');
 		if (isset($aChoice['sub_options']))
@@ -1234,7 +1531,8 @@ EOF
 	
 	protected function GetSourceFilePath()
 	{
-		return APPROOT.'datamodel/installation.xml';
+		$sSourceDir = $this->oWizard->GetParameter('source_dir');
+		return $sSourceDir.'/installation.xml';
 	}
 	
 }
@@ -1286,7 +1584,7 @@ class WizStepSummary extends WizardStep
 	overflow: auto;
 }
 #params_summary div {
-	width:100;
+	width:100%;
 	margin-top:0;
 	padding-top: 0.5em;
 	padding-left: 0;
@@ -1300,7 +1598,7 @@ class WizStepSummary extends WizardStep
 }
 #params_summary div li {
 	list-style: none;
-	width: 100;
+	width: 100%;
 	margin-left:0;
 	padding-left: 0em;
 }
@@ -1323,36 +1621,39 @@ class WizStepSummary extends WizardStep
 }
 EOF
 		);
-		$sMode = $this->oWizard->GetParameter('mode', 'install');
+		
+		$aInstallParams = $this->BuildConfig();
+		
+		$sMode = $aInstallParams['mode'];
 		
 		$sPreinstallationPhase = '';
 		
 		$sDestination = ITOP_APPLICATION.(($sMode == 'install') ? ' version '.ITOP_VERSION.' is about to be installed ' : ' is about to be upgraded ');
-		$sDBDescription = ' <b>existing</b> database <b>'.$this->oWizard->GetParameter('db_name').'</b>';
+		$sDBDescription = ' <b>existing</b> database <b>'.$aInstallParams['database']['name'].'</b>';
 		if (($sMode == 'install') && ($this->oWizard->GetParameter('create_db') == 'yes'))
 		{
-			$sDBDescription = ' <b>new</b> database <b>'.$this->oWizard->GetParameter('db_new_name').'</b>';
+			$sDBDescription = ' <b>new</b> database <b>'.$aInstallParams['database']['name'].'</b>';
 		}
-		$sDestination .= 'into the '.$sDBDescription.' on the server <b>'.$this->oWizard->GetParameter('db_server').'</b>.';
+		$sDestination .= 'into the '.$sDBDescription.' on the server <b>'.$aInstallParams['database']['server'].'</b>.';
 		$oPage->add('<h2>'.$sDestination.'</h2>');
 		
 		$oPage->add('<fieldset id="summary"><legend>Installation Parameters</legend>');
 		$oPage->add('<div id="params_summary">');
 		$oPage->add('<div class="closed"><span class="title">Database Parameters</span><ul>');
-		$oPage->add('<li>Server Name: '.$this->oWizard->GetParameter('db_server').'</li>');
-		$oPage->add('<li>DB User Name: '.$this->oWizard->GetParameter('db_user').'</li>');
-		$oPage->add('<li>DB user password: '.$this->oWizard->GetParameter('db_pwd').'</li>');
+		$oPage->add('<li>Server Name: '.$aInstallParams['database']['server'].'</li>');
+		$oPage->add('<li>DB User Name: '.$aInstallParams['database']['user'].'</li>');
+		$oPage->add('<li>DB user password: '.$aInstallParams['database']['pwd'].'</li>');
 		if (($sMode == 'install') && ($this->oWizard->GetParameter('create_db') == 'yes'))
 		{
-			$oPage->add('<li>Database Name: '.$this->oWizard->GetParameter('db_new_name').' (will be created)</li>');
+			$oPage->add('<li>Database Name: '.$aInstallParams['database']['name'].' (will be created)</li>');
 		}
 		else
 		{
-			$oPage->add('<li>Database Name: '.$this->oWizard->GetParameter('db_name').'</li>');
+			$oPage->add('<li>Database Name: '.$aInstallParams['database']['name'].'</li>');
 		}
-		if ($this->oWizard->GetParameter('db_prefix') != '')
+		if ($aInstallParams['database']['prefix'] != '')
 		{
-			$oPage->add('<li>Prefix for the '.ITOP_APPLICATION.' tables: '.$this->oWizard->GetParameter('db_prefix').'</li>');
+			$oPage->add('<li>Prefix for the '.ITOP_APPLICATION.' tables: '.$aInstallParams['database']['prefix'].'</li>');
 		}
 		else
 		{
@@ -1365,21 +1666,32 @@ EOF
 		$oPage->add('</div>');
 		
 		$oPage->add('<div class="closed"><span class="title">Other Parameters</span><ul>');
-		$oPage->add('<li>Default language: '.$this->oWizard->GetParameter('default_language').'</li>');
-		$oPage->add('<li>URL to access the application: '.$this->oWizard->GetParameter('application_url').'</li>');
-		if ($this->oWizard->GetParameter('sample_data') == 'yes')
+		if ($sMode == 'install')
+		{
+			$oPage->add('<li>Default language: '.$aInstallParams['language'].'</li>');
+		}
+		
+		$oPage->add('<li>URL to access the application: '.$aInstallParams['url'].'</li>');
+		if ($aInstallParams['sample_data'] == 'yes')
 		{
 			$oPage->add('<li>Sample data will be loaded into the database.</li>');
 		}
+		if ($aInstallParams['old_addon'])
+		{
+			$oPage->add('<li>Compatibility mode: Using the version 1.2 of the UserRightsProfiles add-on.</li>');
+		}
 		$oPage->add('</ul></div>');
 		
-		$oPage->add('<div class="closed"><span class="title">Admininistrator Account</span><ul>');
-		$oPage->add('<li>Login: '.$this->oWizard->GetParameter('admin_user').'</li>');
-		$oPage->add('<li>Password: '.$this->oWizard->GetParameter('admin_pwd').'</li>');
-		$oPage->add('<li>Language: '.$this->oWizard->GetParameter('admin_language').'</li>');
-		$oPage->add('</ul></div>');
+		if ($sMode == 'install')
+		{
+			$oPage->add('<div class="closed"><span class="title">Admininistrator Account</span><ul>');
+			$oPage->add('<li>Login: '.$aInstallParams['admin_account']['user'].'</li>');
+			$oPage->add('<li>Password: '.$aInstallParams['admin_account']['pwd'].'</li>');
+			$oPage->add('<li>Language: '.$aInstallParams['admin_account']['language'].'</li>');
+			$oPage->add('</ul></div>');
+		}
 		
-		$aMiscOptions = json_decode($this->oWizard->GetParameter('misc_options', '[]'), true /* bAssoc */);
+		$aMiscOptions = $aInstallParams['options'];
 		if (count($aMiscOptions) > 0)
 		{
 			$oPage->add('<div class="closed"><span class="title">Miscellaneous Options</span><ul>');
@@ -1391,100 +1703,8 @@ EOF
 			
 		}
 		
-		$aSelectedModules = json_decode($this->oWizard->GetParameter('selected_modules'), true);
-/*		
-		$oPage->add('<ul>Selected modules:');
-		sort($aSelectedModules);
-		foreach($aSelectedModules as $sModuleId)
-		{
-			$oPage->add('<li>'.$sModuleId.'</li>');
-			
-		}
-		$oPage->add('</ul>');
-*/		
-		$oPage->add_ready_script(
-<<<EOF
-	$("#params_summary div").addClass('closed');
-	$("#params_summary .title").click(function() { $(this).parent().toggleClass('closed'); } );
-	$("#btn_next").bind("click.install", function(event) {
-			$('#summary').hide();
-			$('#installation_progress').show();
-			$(this).attr("disabled", "disabled"); event.preventDefault(); ExecuteStep("");
-	});
-	$("#wiz_form").data("installation_status", "not started")
-EOF
-		);
+		$aSelectedModules = $aInstallParams['selected_modules'];
 		
-		// Prepare the parameters to execute the installation asynchronously
-		
-		$sBackupDestination = '';
-		$sConfigurationFile = '';
-		$sDBName = $this->oWizard->GetParameter('db_name');
-		if ($sMode == 'upgrade')
-		{
-			if ($this->oWizard->GetParameter('db_backup', false))
-			{
-				$sSourceDir = $this->oWizard->GetParameter('source_dir', '');
-				if (!empty($sSourceDir))
-				{
-					$aPreviousInstance = SetupUtils::GetPreviousInstance($sSourceDir);
-					if ($aPreviousInstance['found'])
-					{
-						$sConfigurationFile = $aPreviousInstance['configuration_file'];
-					}
-				}
-			}
-		}
-		else
-		{
-			
-			$sDBNewName = $this->oWizard->GetParameter('db_new_name', '');
-			if ($sDBNewName != '')
-			{
-				$sDBName = $sDBNewName; // Database will be created
-			}
-		}
-		
-		$aInstallParams = array (
-		  'mode' => $sMode,
-		  'preinstall' => array (
-		    'copies' => array (
-//		      0 => array (
-//		        'source' => '',
-//		        'destination' => '',
-//		      ),
-		    ),
-		  ),
-		  'source_dir' => 'datamodel',
-		  'target_env' => 'production',
-		  'workspace_dir' => '',
-		  'database' => array (
-		    'server' => $this->oWizard->GetParameter('db_server'),
-		    'user' => $this->oWizard->GetParameter('db_user'),
-		    'pwd' => $this->oWizard->GetParameter('db_pwd'),
-		    'name' => $sDBName,
-		    'prefix' => $this->oWizard->GetParameter('db_prefix'),
-		  ),
-		  'url' => $this->oWizard->GetParameter('application_url'),
-		  'admin_account' => array (
-		    'user' => $this->oWizard->GetParameter('admin_user'),
-		    'pwd' => $this->oWizard->GetParameter('admin_pwd'),
-		    'language' => $this->oWizard->GetParameter('admin_language'),
-		  ),
-		  'language' => $this->oWizard->GetParameter('default_language'),
-		  'selected_modules' =>  $aSelectedModules,
-		  'sample_data' => ($this->oWizard->GetParameter('sample_data', '') == 'yes') ? true : false ,
-		  'options' => json_decode($this->oWizard->GetParameter('misc_options', '[]'), true),
-		);
-
-		if ($sBackupDestination != '')
-		{
-			$aInstallParams['backup'] = array (
-			      'destination' => $sBackupDestination,
-			      'configuration_file' => $sConfigurationFile,
-			);
-		}
-		$sJSONData = json_encode($aInstallParams);
 		if (isset($aMiscOptions['generate_config']))
 		{
 			$oDoc = new DOMDocument('1.0', 'UTF-8');
@@ -1499,7 +1719,6 @@ EOF
 			$oPage->add(htmlentities($sXML, ENT_QUOTES, 'UTF-8'));
 			$oPage->add('</pre></ul></div>');
 		}
-		
 	
 		$oPage->add('</div>'); // params_summary
 		$oPage->add('</fieldset>');
@@ -1511,7 +1730,127 @@ EOF
 		$oPage->add('</div>'); // progress_content
 		$oPage->add('</fieldset>');
 		
+		$sJSONData = json_encode($aInstallParams);
 		$oPage->add('<input type="hidden" id="installer_parameters" value="'.htmlentities($sJSONData, ENT_QUOTES, 'UTF-8').'"/>');
+
+		$oPage->add_ready_script(
+<<<EOF
+	$("#params_summary div").addClass('closed');
+	$("#params_summary .title").click(function() { $(this).parent().toggleClass('closed'); } );
+	$("#btn_next").bind("click.install", function(event) {
+			$('#summary').hide();
+			$('#installation_progress').show();
+			$(this).attr("disabled", "disabled"); event.preventDefault(); ExecuteStep("");
+	});
+	$("#wiz_form").data("installation_status", "not started")
+EOF
+		);
+	}
+	
+	/**
+	 * Prepare the parameters to execute the installation asynchronously
+	 * @return Hash A big hash array that can be converted to XML or JSON with all the needed parameters
+	 */
+	protected function BuildConfig()
+	{
+		$sMode = $this->oWizard->GetParameter('install_mode', 'install');
+		$aSelectedModules = json_decode($this->oWizard->GetParameter('selected_modules'), true);
+		$sBackupDestination = '';
+		$sPreviousConfigurationFile = '';
+		$sDBName = $this->oWizard->GetParameter('db_name');
+		if ($sMode == 'upgrade')
+		{
+			$sPreviousVersionDir = $this->oWizard->GetParameter('previous_version_dir', '');
+			if (!empty($sPreviousVersionDir))
+			{
+				$aPreviousInstance = SetupUtils::GetPreviousInstance($sPreviousVersionDir);
+				if ($aPreviousInstance['found'])
+				{
+					$sPreviousConfigurationFile = $aPreviousInstance['configuration_file'];
+				}
+			}
+			
+			if ($this->oWizard->GetParameter('db_backup', false))
+			{
+				$sBackupDestination = $this->oWizard->GetParameter('db_backup_path', '');
+			}
+		}
+		else
+		{
+			
+			$sDBNewName = $this->oWizard->GetParameter('db_new_name', '');
+			if ($sDBNewName != '')
+			{
+				$sDBName = $sDBNewName; // Database will be created
+			}
+		}
+		
+		$sSourceDir = $this->oWizard->GetParameter('source_dir');
+		$aCopies = array();
+		if (($sMode == 'upgrade') && ($this->oWizard->GetParameter('upgrade_type') == 'keep-previous'))
+		{
+			$sPreviousVersionDir = $this->oWizard->GetParameter('previous_version_dir');
+			$aCopies[] = array('source' => $sSourceDir, 'destination' => 'modules'); // Source is an absolute path, destination is relative to APPROOT
+			$aCopies[] = array('source' => $sPreviousVersionDir.'/portal', 'destination' => 'portal'); // Source is an absolute path, destination is relative to APPROOT
+			$sSourceDir = APPROOT.'modules';
+		}
+		
+		if (($sMode == 'upgrade'))
+		{
+			// Copy the previous extensions, if any
+			$sPreviousExtensionsDir = $this->oWizard->GetParameter('copy_extensions_from');
+			if (is_dir($sPreviousExtensionsDir))
+			{
+				// Copy the extensions one by one to merge them with the existing extensions in /extensions
+				$aExtensions = glob($sPreviousExtensionsDir.'/*', GLOB_ONLYDIR);
+				foreach($aExtensions as $sDirPath)
+				{
+					$sExtName = basename($sDirPath);
+					$aCopies[] = array('source' => $sDirPath, 'destination' => 'extensions/'.$sExtName); // Source is an absolute path, destination is relative to APPROOT
+				}
+			}
+		}
+				
+		$aInstallParams = array (
+			'mode' => $sMode,
+			'preinstall' => array (
+				'copies' => $aCopies,
+				// 'backup' => see below
+			),
+			'source_dir' => str_replace(APPROOT, '', $sSourceDir),
+			'datamodel_version' => $this->oWizard->GetParameter('datamodel_version'), //TODO: let the installer compute this automatically...
+			'previous_configuration_file' => $sPreviousConfigurationFile,
+			'extensions_dir' => 'extensions',
+			'target_env' => 'production',
+			'workspace_dir' => '',
+			'database' => array (
+				'server' => $this->oWizard->GetParameter('db_server'),
+				'user' => $this->oWizard->GetParameter('db_user'),
+				'pwd' => $this->oWizard->GetParameter('db_pwd'),
+				'name' => $sDBName,
+				'prefix' => $this->oWizard->GetParameter('db_prefix'),
+			),
+			'url' => $this->oWizard->GetParameter('application_url'),
+			'admin_account' => array (
+				'user' => $this->oWizard->GetParameter('admin_user'),
+				'pwd' => $this->oWizard->GetParameter('admin_pwd'),
+				'language' => $this->oWizard->GetParameter('admin_language'),
+			),
+			'language' => $this->oWizard->GetParameter('default_language'),
+			'selected_modules' =>  $aSelectedModules,
+			'sample_data' => ($this->oWizard->GetParameter('sample_data', '') == 'yes') ? true : false ,
+			'old_addon' => $this->oWizard->GetParameter('old_addon', false), // whether or not to use the "old" userrights profile addon
+			'options' => json_decode($this->oWizard->GetParameter('misc_options', '[]'), true),
+		);
+
+		if ($sBackupDestination != '')
+		{
+			$aInstallParams['backup'] = array (
+				'destination' => $sBackupDestination,
+				'configuration_file' => $sPreviousConfigurationFile,
+			);
+		}
+		return $aInstallParams;
 	}
 	
 	public function AsyncAction(WebPage $oPage, $sCode, $aParameters)
@@ -1658,4 +1997,14 @@ class WizStepDone extends WizardStep
 	{
 		return false;
 	}
+	
+	/**
+	 * Tells whether this step of the wizard requires that the configuration file be writable
+	 * @return bool True if the wizard will possibly need to modify the configuration at some point
+	 */
+	public function RequiresWritableConfig()
+	{
+		return false; //This step executes once the config was written and secured
+	}
+	
 }