diff --git a/setup/feature_removal/SetupAudit.php b/setup/feature_removal/SetupAudit.php
index 7cdcaa3a2..35c4628d9 100644
--- a/setup/feature_removal/SetupAudit.php
+++ b/setup/feature_removal/SetupAudit.php
@@ -10,11 +10,11 @@ class SetupAudit extends AbstractSetupAudit
 	private string $sEnvBefore;
 	private string $sEnvAfter;
 
-	public function __construct(string $sEnvBefore)
+	public function __construct(string $sEnvBefore, ?string $sEnvAfter = null)
 	{
 		parent::__construct();
 		$this->sEnvBefore = $sEnvBefore;
-		$this->sEnvAfter = "$sEnvBefore-build";
+		$this->sEnvAfter = $sEnvAfter ?? "$sEnvBefore-build";
 	}
 
 	public function ComputeClasses(): void
diff --git a/setup/runtimeenv.class.inc.php b/setup/runtimeenv.class.inc.php
index 80f7ad385..a8918b5cd 100644
--- a/setup/runtimeenv.class.inc.php
+++ b/setup/runtimeenv.class.inc.php
@@ -25,6 +25,7 @@
  */
 
 use Combodo\iTop\PhpParser\Evaluation\PhpExpressionEvaluator;
+use Combodo\iTop\Setup\FeatureRemoval\SetupAudit;
 use Combodo\iTop\Setup\ModuleDiscovery\ModuleFileReader;
 use Combodo\iTop\Setup\ModuleDiscovery\ModuleFileReaderException;
 
@@ -308,7 +309,7 @@ class RunTimeEnvironment
 			$sModule = $oModule->GetName();
 			$bIsExtra = $this->GetExtensionMap()->ModuleIsChosenAsPartOfAnExtension($sModule, iTopExtension::SOURCE_REMOTE);
 			if (array_key_exists($sModule, $aAvailableModules)) {
-				if (($aAvailableModules[$sModule]['installed_version'] != '') ||  $bIsExtra && !$oModule->IsAutoSelect()) { //Extra modules are always unless they are 'AutoSelect'
+				if (($aAvailableModules[$sModule]['installed_version'] != '') || $bIsExtra && !$oModule->IsAutoSelect()) { //Extra modules are always unless they are 'AutoSelect'
 					$aRet[$oModule->GetName()] = $oModule;
 				}
 			}
@@ -327,9 +328,10 @@ class RunTimeEnvironment
 						$bSelected = $oPhpExpressionEvaluator->ParseAndEvaluateBooleanExpression($oModule->GetAutoSelect());
 						if ($bSelected) {
 							$aRet[$oModule->GetName()] = $oModule; // store the Id of the selected module
-							$bModuleAdded  = true;
+							$bModuleAdded = true;
 						}
-					} catch (ModuleFileReaderException $e) {
+					}
+					catch (ModuleFileReaderException $e) {
 						//do nothing. logged already
 					}
 				}
@@ -345,56 +347,6 @@ class RunTimeEnvironment
 		return $aRet;
 	}
 
-	/**
-	 * Compile the data model by imitating the given environment
-	 * The list of modules to be installed in the build environment is:
-	 *  - the list of modules present in the "source_dir" (defined by the source environment) which are marked as "installed" in the source environment's database
-	 *  - plus the list of modules present in the "extra" directory of the build environment: data/<build_environment>-modules/
-	 *
-	 * @param string $sSourceEnv The name of the source environment to 'imitate'
-	 * @param bool $bUseSymLinks Whether to create symbolic links instead of copies
-	 *
-	 * @return string[]
-	 */
-	public function CompileFrom($sSourceEnv, $bUseSymLinks = null)
-	{
-		$oSourceConfig = new Config(utils::GetConfigFilePath($sSourceEnv));
-		$sSourceDir = $oSourceConfig->Get('source_dir');
-
-		$sSourceDirFull = APPROOT.$sSourceDir;
-		// Do load the required modules
-		//
-		$oFactory = new ModelFactory($sSourceDirFull);
-		$aModulesToCompile = $this->GetMFModulesToCompile($sSourceEnv, $sSourceDir);
-		$oModule = null;
-		foreach ($aModulesToCompile as $oModule) {
-			if ($oModule instanceof MFDeltaModule) {
-				// Just before loading the delta, let's save an image of the datamodel
-				// in case there is no delta the operation will be done after the end of the loop
-				$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'.xml');
-			}
-			$oFactory->LoadModule($oModule);
-		}
-
-		if (!is_null($oModule) && ($oModule instanceof MFDeltaModule)) {
-			// A delta was loaded, let's save a second copy of the datamodel
-			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'-with-delta.xml');
-		} else {
-			// No delta was loaded, let's save the datamodel now
-			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'.xml');
-		}
-
-		$sBuildDir = APPROOT.'env-'.$this->sBuildEnv;
-		self::MakeDirSafe($sBuildDir);
-		$bSkipTempDir = ($this->sFinalEnv != $this->sBuildEnv); // No need for a temporary directory if sBuildEnv is already a temporary directory
-		$oMFCompiler = new MFCompiler($oFactory, $this->sFinalEnv);
-		$oMFCompiler->Compile($sBuildDir, null, $bUseSymLinks, $bSkipTempDir);
-
-		MetaModel::ResetAllCaches($this->sBuildEnv);
-
-		return array_keys($aModulesToCompile);
-	}
-
 	/**
 	 * Helper function to create the database structure
 	 *
@@ -509,7 +461,7 @@ class RunTimeEnvironment
 					}
 				}
 				foreach ($aPredefinedObjects as $iRefId => $aObjValues) {
-					if (! array_key_exists($iRefId, $aDBIds)) {
+					if (!array_key_exists($iRefId, $aDBIds)) {
 						$oNewObj = MetaModel::NewObject($sClass);
 						$oNewObj->SetKey($iRefId);
 						foreach ($aObjValues as $sAttCode => $value) {
@@ -650,7 +602,8 @@ class RunTimeEnvironment
 	{
 		try {
 			$aSelectInstall = ModuleInstallationRepository::GetInstance()->ReadFromDB($oConfig);
-		} catch (MySQLException $e) {
+		}
+		catch (MySQLException $e) {
 			// No database or erroneous information
 			$this->log_error('Can not connect to the database: host: '.$oConfig->Get('db_host').', user:'.$oConfig->Get('db_user').', pwd:'.$oConfig->Get('db_pwd').', db name:'.$oConfig->Get('db_name'));
 			$this->log_error('Exception '.$e->getMessage());
@@ -708,14 +661,17 @@ class RunTimeEnvironment
 	{
 		SetupLog::Error($sText);
 	}
+
 	protected function log_warning($sText)
 	{
 		SetupLog::Warning($sText);
 	}
+
 	protected function log_info($sText)
 	{
 		SetupLog::Info($sText);
 	}
+
 	protected function log_ok($sText)
 	{
 		SetupLog::Ok($sText);
@@ -747,10 +703,16 @@ class RunTimeEnvironment
 		if ($oLatestDM == null) {
 			return '0.0.0';
 		}
+
 		return $oLatestDM->Get('version');
 	}
 
-	public function Commit()
+	/**
+	 * Move the build env to the final env if all the steps went ok
+	 *
+	 * @return void
+	 */
+	public function Commit(): void
 	{
 		if ($this->sFinalEnv != $this->sBuildEnv) {
 			if (file_exists(utils::GetDataPath().$this->sBuildEnv.'.delta.xml')) {
@@ -808,12 +770,13 @@ class RunTimeEnvironment
 	/**
 	 * Overwrite or create the destination file
 	 *
-	 * @param $sSource
-	 * @param $sDest
+	 * @param string $sSource
+	 * @param string $sDest
 	 * @param bool $bSourceMustExist
-	 * @throws Exception
+	 *
+	 * @throws \Exception
 	 */
-	protected function CommitFile($sSource, $sDest, $bSourceMustExist = true)
+	protected function CommitFile(string $sSource, string $sDest, bool $bSourceMustExist = true): void
 	{
 		if (file_exists($sSource)) {
 			SetupUtils::builddir(dirname($sDest));
@@ -847,6 +810,7 @@ class RunTimeEnvironment
 	 * @param $sDest
 	 * @param boolean $bSourceMustExist
 	 * @param boolean $bRemoveSource If true $sSource will be removed, otherwise $sSource will just be emptied
+	 *
 	 * @throws Exception
 	 */
 	protected function CommitDir($sSource, $sDest, $bSourceMustExist = true, $bRemoveSource = true)
@@ -875,9 +839,11 @@ class RunTimeEnvironment
 
 	/**
 	 * Call the given handler method for all selected modules having an installation handler
+	 *
 	 * @param array[] $aAvailableModules
 	 * @param string $sHandlerName
-	 *  @param string[]|null $aSelectedModules
+	 * @param string[]|null $aSelectedModules
+	 *
 	 * @throws CoreException
 	 */
 	public function CallInstallerHandlers($aAvailableModules, $sHandlerName, $aSelectedModules = null)
@@ -915,15 +881,16 @@ class RunTimeEnvironment
 		if (is_callable($aCallSpec)) {
 			try {
 				call_user_func_array($aCallSpec, $aArgs);
-			} catch (Exception $e) {
+			}
+			catch (Exception $e) {
 				$sModuleId = $aModuleInfo[ModuleFileReader::MODULE_INFO_ID] ?? "";
 				$sErrorMessage = "Module $sModuleId : error when calling module installer class $sModuleInstallerClass for $sHandlerName handler";
 				$aExceptionContextData = [
-					'ModulelId' => $sModuleId,
-					'ModuleInstallerClass' => $sModuleInstallerClass,
+					'ModulelId'              => $sModuleId,
+					'ModuleInstallerClass'   => $sModuleInstallerClass,
 					'ModuleInstallerHandler' => $sHandlerName,
-					'ExceptionClass' => get_class($e),
-					'ExceptionMessage' => $e->getMessage(),
+					'ExceptionClass'         => get_class($e),
+					'ExceptionMessage'       => $e->getMessage(),
 				];
 				throw new CoreException($sErrorMessage, $aExceptionContextData, '', $e);
 			}
@@ -932,9 +899,10 @@ class RunTimeEnvironment
 
 	/**
 	 * Load data from XML files for the selected modules (structural data and/or sample data)
+	 *
 	 * @param array[] $aAvailableModules All available modules and their definition
 	 * @param bool $bSampleData Wether or not to load sample data
-	 *  @param null|string[] $aSelectedModules List of selected modules
+	 * @param null|string[] $aSelectedModules List of selected modules
 	 */
 	public function LoadData($aAvailableModules, $bSampleData, $aSelectedModules = null)
 	{
@@ -1011,9 +979,11 @@ class RunTimeEnvironment
 
 	/**
 	 * Merge two arrays of file names, adding the relative path to the files provided in the array to merge
+	 *
 	 * @param string[] $aSourceArray
 	 * @param string $sBaseDir
 	 * @param string[] $aFilesToMerge
+	 *
 	 * @return string[]
 	 */
 	protected static function MergeWithRelativeDir($aSourceArray, $sBaseDir, $aFilesToMerge)
@@ -1022,14 +992,16 @@ class RunTimeEnvironment
 		foreach ($aFilesToMerge as $sFile) {
 			$aToMerge[] = $sBaseDir.'/'.$sFile;
 		}
+
 		return array_merge($aSourceArray, $aToMerge);
 	}
 
 	/**
 	 * Check the MetaModel for some common pitfall (class name too long, classes requiring too many joins...)
 	 * The check takes about 900 ms for 200 classes
-	 * @throws Exception
+	 *
 	 * @return string
+	 * @throws Exception
 	 */
 	public function CheckMetaModel()
 	{
@@ -1043,7 +1015,7 @@ class RunTimeEnvironment
 
 			$oSearch = new DBObjectSearch($sClass);
 			$oSearch->SetShowObsoleteData(false);
-			$oSQLQuery = $oSearch->GetSQLQueryStructure(null, false);
+			$oSQLQuery = $oSearch->GetSQLQueryStructure([], false);
 			$sViewName = MetaModel::DBGetView($sClass);
 			if (strlen($sViewName) > 64) {
 				throw new Exception("Class name too long for class: '$sClass'. The name of the corresponding view ($sViewName) would exceed MySQL's limit for the name of a table (64 characters).");
@@ -1062,4 +1034,226 @@ class RunTimeEnvironment
 
 		return sprintf("Checked %d classes in %.1f ms. No error found.\n", $iCount, $fDuration * 1000.0);
 	}
-} // End of class
+
+	public function DataToCleanupAudit()
+	{
+		$oSetupAudit = new SetupAudit('production', $this->sBuildEnv);
+
+		//Make sure the MetaModel is started before analysing for issues
+		$sConfFile = utils::GetConfigFilePath($this->sBuildEnv);
+		MetaModel::Startup($sConfFile, false, false, false, $this->sBuildEnv);
+		$oSetupAudit->GetIssues(true);
+		$iCount = $oSetupAudit->GetDataToCleanupCount();
+
+		if ($iCount > 0) {
+			throw new Exception("$iCount elements require data adjustments or cleanup in the backoffice prior to upgrading iTop", DataAuditSequencer::DATA_AUDIT_FAILED);
+		}
+	}
+
+	public function CopySetupFiles(): void
+	{
+		$sSourceEnv = 'production';
+		$sDestinationEnv = $this->sBuildEnv;
+
+		if ($sDestinationEnv != $sSourceEnv) {
+			SetupUtils::CopyFile(utils::GetDataPath().$sSourceEnv.'.delta.xml', utils::GetDataPath().$sDestinationEnv.'.delta.xml');
+			SetupUtils::copydir(utils::GetDataPath().$sSourceEnv.'-modules/', utils::GetDataPath().$sDestinationEnv.'-modules/');
+
+			// Copy the config file
+			//
+			$sFinalConfig = APPCONF.$sDestinationEnv.'/config-itop.php';
+			if (is_file($sFinalConfig)) {
+				chmod($sFinalConfig, 0770); // In case it exists: RWX for owner and group, nothing for others
+			}
+			SetupUtils::copydir(APPCONF.$sSourceEnv, APPCONF.$sDestinationEnv);
+			if (is_file($sFinalConfig)) {
+				chmod($sFinalConfig, 0440); // Read-only for owner and group, nothing for others
+			}
+
+			MetaModel::ResetAllCaches($sDestinationEnv);
+		}
+	}
+
+	/**
+	 * Compile the data model by imitating the given environment
+	 * The list of modules to be installed in the build environment is:
+	 *  - the list of modules present in the "source_dir" (defined by the source environment) which are marked as "installed" in the source environment's database
+	 *  - plus the list of modules present in the "extra" directory of the build environment: data/<build_environment>-modules/
+	 *
+	 * @param string $sSourceEnv The name of the source environment to 'imitate'
+	 * @param null $bUseSymLinks Whether to create symbolic links instead of copies
+	 *
+	 * @return string[]
+	 * @throws \ConfigException
+	 * @throws \CoreException
+	 */
+	public function CompileFrom($sSourceEnv, $bUseSymLinks = null)
+	{
+		$oSourceConfig = new Config(utils::GetConfigFilePath($sSourceEnv));
+		$sSourceDir = $oSourceConfig->Get('source_dir');
+
+		$sSourceDirFull = APPROOT.$sSourceDir;
+		// Do load the required modules
+		//
+		$oFactory = new ModelFactory($sSourceDirFull);
+		$aModulesToCompile = $this->GetMFModulesToCompile($sSourceEnv, $sSourceDir);
+		$oModule = null;
+		foreach ($aModulesToCompile as $oModule) {
+			if ($oModule instanceof MFDeltaModule) {
+				// Just before loading the delta, let's save an image of the datamodel
+				// in case there is no delta the operation will be done after the end of the loop
+				$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'.xml');
+			}
+			$oFactory->LoadModule($oModule);
+		}
+
+		if (!is_null($oModule) && ($oModule instanceof MFDeltaModule)) {
+			// A delta was loaded, let's save a second copy of the datamodel
+			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'-with-delta.xml');
+		} else {
+			// No delta was loaded, let's save the datamodel now
+			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$this->sBuildEnv.'.xml');
+		}
+
+		$sBuildDir = APPROOT.'env-'.$this->sBuildEnv;
+		self::MakeDirSafe($sBuildDir);
+		$bSkipTempDir = ($this->sFinalEnv != $this->sBuildEnv); // No need for a temporary directory if sBuildEnv is already a temporary directory
+		$oMFCompiler = new MFCompiler($oFactory, $this->sFinalEnv);
+		$oMFCompiler->Compile($sBuildDir, null, $bUseSymLinks, $bSkipTempDir);
+
+		MetaModel::ResetAllCaches($this->sBuildEnv);
+
+		return array_keys($aModulesToCompile);
+	}
+
+
+	/**
+	 * @param array $aRemovedExtensionCodes
+	 * @param array $aSelectedModules
+	 * @param string $sSourceDir
+	 * @param string $sExtensionDir
+	 * @param boolean $bUseSymbolicLinks
+	 *
+	 * @return void
+	 * @throws \ConfigException
+	 * @throws \CoreException
+	 *
+	 */
+	public function DoCompile(array $aRemovedExtensionCodes, array $aSelectedModules, string $sSourceDir, string $sExtensionDir, bool $bUseSymbolicLinks = false): void
+	{
+		SetupLog::Info('Compiling data model.');
+
+		$sEnvironment = $this->sBuildEnv;
+		$sBuildPath = $this->GetBuildDir();
+
+		$sSourcePath = APPROOT.$sSourceDir;
+		$aDirsToScan = [$sSourcePath];
+		$sExtensionsPath = APPROOT.$sExtensionDir;
+		if (is_dir($sExtensionsPath)) {
+			// if the extensions dir exists, scan it for additional modules as well
+			$aDirsToScan[] = $sExtensionsPath;
+		}
+		$sExtraPath = APPROOT.'/data/'.$sEnvironment.'-modules/';
+		if (is_dir($sExtraPath)) {
+			// if the extra dir exists, scan it for additional modules as well
+			$aDirsToScan[] = $sExtraPath;
+		}
+
+		if (!is_dir($sSourcePath)) {
+			throw new Exception("Failed to find the source directory '$sSourcePath', please check the rights of the web server");
+		}
+
+		if (!is_dir($sBuildPath)) {
+			if (!mkdir($sBuildPath)) {
+				throw new Exception("Failed to create directory '$sBuildPath', please check the rights of the web server");
+			} else {
+				// adjust the rights if and only if the directory was just created
+				// owner:rwx user/group:rx
+				chmod($sBuildPath, 0755);
+			}
+		} elseif ($this->IsInItop($sBuildPath)) {
+			// If the directory is under the root folder - as expected - let's clean-it before compiling
+			SetupUtils::tidydir($sBuildPath);
+		}
+
+		$oExtensionsMap = new iTopExtensionsMap('production', $aDirsToScan);
+		// Removed modules are stored as static for FindModules()
+		$oExtensionsMap->DeclareExtensionAsRemoved($aRemovedExtensionCodes);
+
+		$oFactory = new ModelFactory($aDirsToScan);
+
+		$oDictModule = new MFDictModule('dictionaries', 'iTop Dictionaries', APPROOT.'dictionaries');
+		$oFactory->LoadModule($oDictModule);
+
+		$sDeltaFile = APPROOT.'core/datamodel.core.xml';
+		if (file_exists($sDeltaFile)) {
+			$oCoreModule = new MFCoreModule('core', 'Core Module', $sDeltaFile);
+			$oFactory->LoadModule($oCoreModule);
+		}
+		$sDeltaFile = APPROOT.'application/datamodel.application.xml';
+		if (file_exists($sDeltaFile)) {
+			$oApplicationModule = new MFCoreModule('application', 'Application Module', $sDeltaFile);
+			$oFactory->LoadModule($oApplicationModule);
+		}
+
+		$aModules = $oFactory->FindModules();
+
+		foreach ($aModules as $oModule) {
+			$sModule = $oModule->GetName();
+			if (in_array($sModule, $aSelectedModules)) {
+				$oFactory->LoadModule($oModule);
+			}
+		}
+
+		// Dump the "reference" model, just before loading any actual delta
+		$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$sEnvironment.'.xml');
+
+		$sDeltaFile = utils::GetDataPath().$sEnvironment.'.delta.xml';
+		if (file_exists($sDeltaFile)) {
+			$oDelta = new MFDeltaModule($sDeltaFile);
+			$oFactory->LoadModule($oDelta);
+			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$sEnvironment.'-with-delta.xml');
+		}
+
+		$oMFCompiler = new MFCompiler($oFactory, $sEnvironment);
+		$oMFCompiler->Compile($sBuildPath, null, $bUseSymbolicLinks, false, false);
+		SetupLog::Info("Data model successfully compiled to '$sBuildPath'.");
+
+		$sCacheDir = APPROOT.'/data/cache-'.$sEnvironment.'/';
+		SetupUtils::builddir($sCacheDir);
+		SetupUtils::tidydir($sCacheDir);
+
+
+		// Set an "Instance UUID" identifying this machine based on a file located in the data directory
+		$sInstanceUUIDFile = utils::GetDataPath().'instance.txt';
+		SetupUtils::builddir(utils::GetDataPath());
+		if (!file_exists($sInstanceUUIDFile)) {
+			$sInstanceUUID = utils::CreateUUID('filesystem');
+			file_put_contents($sInstanceUUIDFile, $sInstanceUUID);
+		}
+	}
+
+	protected function IsInItop(string $sPath): bool
+	{
+		$sFileRealPath = realpath($sPath);
+		if ($sFileRealPath === false) {
+			return false;
+		}
+
+		$sRealBasePath = realpath(APPROOT); // avoid problems when having '/' on Windows for example
+		if (!self::StartsWith($sFileRealPath, $sRealBasePath)) {
+			return false;
+		}
+
+		return true;
+	}
+
+	protected static function StartsWith(string $sHaystack, string $sNeedle): bool
+	{
+		if (strlen($sNeedle) > strlen($sHaystack)) {
+			return false;
+		}
+
+		return substr_compare($sHaystack, $sNeedle, 0, strlen($sNeedle)) === 0;
+	}
+}
diff --git a/setup/sequencers/ApplicationInstallSequencer.php b/setup/sequencers/ApplicationInstallSequencer.php
index a2a49c68b..580cc78e3 100644
--- a/setup/sequencers/ApplicationInstallSequencer.php
+++ b/setup/sequencers/ApplicationInstallSequencer.php
@@ -45,14 +45,22 @@ class ApplicationInstallSequencer extends StepSequencer
 
 	protected Config $oConfig;
 
+	protected RunTimeEnvironment $oRunTimeEnvironment;
+
 	/**
 	 * @param \Parameters $oParams
 	 *
 	 * @throws \ConfigException
 	 * @throws \CoreException
 	 */
-	public function __construct(Parameters $oParams)
+	public function __construct(Parameters $oParams, ?RunTimeEnvironment $oRunTimeEnvironment = null)
 	{
+		if (is_null($oRunTimeEnvironment)) {
+			$sEnvironment = $oParams->Get('target_env', 'production');
+			$oRunTimeEnvironment = new RunTimeEnvironment($sEnvironment, false);
+		}
+		$this->oRunTimeEnvironment = $oRunTimeEnvironment;
+
 		$this->oParams = $oParams;
 
 		$aParamValues = $oParams->GetParamForConfigArray();
@@ -99,26 +107,7 @@ class ApplicationInstallSequencer extends StepSequencer
 		return $oConfig;
 	}
 
-	protected function DoLogParameters($sPrefix = 'install-', $sOperation = 'Installation')
-	{
-		// Log the parameters...
-		$oDoc = new DOMDocument('1.0', 'UTF-8');
-		$oDoc->preserveWhiteSpace = false;
-		$oDoc->formatOutput = true;
-		$this->oParams->ToXML($oDoc, null, 'installation');
-		$sXML = $oDoc->saveXML();
-		$sSafeXml = preg_replace("|<pwd>([^<]*)</pwd>|", "<pwd>**removed**</pwd>", $sXML);
-		SetupLog::Info("======= ".$sOperation." starts =======\nParameters:\n$sSafeXml\n");
 
-		// Save the response file as a stand-alone file as well
-		$sFileName = $sPrefix.date('Y-m-d');
-		$index = 0;
-		while (file_exists(APPROOT.'log/'.$sFileName.'.xml')) {
-			$index++;
-			$sFileName = $sPrefix.date('Y-m-d').'-'.$index;
-		}
-		file_put_contents(APPROOT.'log/'.$sFileName.'.xml', $sSafeXml);
-	}
 
 	/**
 	 * Executes the next step of the installation and reports about the progress
@@ -137,6 +126,14 @@ class ApplicationInstallSequencer extends StepSequencer
 			$this->EnterReadOnlyMode();
 			switch ($sStep) {
 				case '':
+					if (in_array('log-parameters', $this->oParams->Get('optional_steps', []))) {
+						return $this->GetNextStep('log-parameters', 'Log parameters', 0);
+					}
+					return $this->GetNextStep('copy', 'Copying data model files', 5);
+
+				case 'log-parameters':
+					$this->DoLogParameters('data-audit-', 'Data Audit');
+					return $this->GetNextStep('copy', 'Copying data model files', 5);
 
 					$this->DoLogParameters();
 
@@ -374,26 +371,6 @@ class ApplicationInstallSequencer extends StepSequencer
 		SetupUtils::ExitReadOnlyMode();
 	}
 
-	protected function DoCopy($aCopies)
-	{
-		$aReports = [];
-		foreach ($aCopies as $aCopy) {
-			$sSource = $aCopy['source'];
-			$sDestination = APPROOT.$aCopy['destination'];
-
-			SetupUtils::builddir($sDestination);
-			SetupUtils::tidydir($sDestination);
-			SetupUtils::copydir($sSource, $sDestination);
-			$aReports[] = "'{$aCopy['source']}' to '{$aCopy['destination']}' (OK)";
-		}
-		if (count($aReports) > 0) {
-			$sReport = "Copies: ".count($aReports).': '.implode('; ', $aReports);
-		} else {
-			$sReport = "No file copy";
-		}
-		return $sReport;
-	}
-
 	/**
 	 * @param string $sBackupFileFormat
 	 * @param string $sSourceConfigFile
@@ -416,160 +393,6 @@ class ApplicationInstallSequencer extends StepSequencer
 		$oBackup->CreateCompressedBackup($sTargetFile, $sSourceConfigFile);
 	}
 
-	/**
-	 * @param array $aRemovedExtensionCodes
-	 * @param array $aSelectedModules
-	 * @param string $sSourceDir
-	 * @param string $sExtensionDir
-	 * @param boolean $bUseSymbolicLinks
-	 *
-	 * @return void
-	 * @throws \ConfigException
-	 * @throws \CoreException
-	 *
-	 * @since 3.1.0 N°2013 added the aParamValues param
-	 */
-	protected function DoCompile($aRemovedExtensionCodes, $aSelectedModules, $sSourceDir, $sExtensionDir, $bUseSymbolicLinks = null, $bEnterMaintenanceMode = true)
-	{
-		/**
-		 * @since 3.2.0 move the ContextTag init at the very beginning of the method
-		 * @noinspection PhpUnusedLocalVariableInspection
-		 */
-		$oContextTag = new ContextTag(ContextTag::TAG_SETUP);
-
-		SetupLog::Info("Compiling data model.");
-
-		require_once(APPROOT.'setup/modulediscovery.class.inc.php');
-		require_once(APPROOT.'setup/modelfactory.class.inc.php');
-		require_once(APPROOT.'setup/compiler.class.inc.php');
-
-		$aParamValues = $this->oParams->GetParamForConfigArray();
-		$sEnvironment = $this->GetTargetEnv();
-		$sTargetDir = $this->GetTargetDir();
-
-		if (empty($sSourceDir) || empty($sTargetDir)) {
-			throw new Exception("missing parameter source_dir and/or target_dir");
-		}
-
-		$sSourcePath = APPROOT.$sSourceDir;
-		$aDirsToScan = [$sSourcePath];
-		$sExtensionsPath = APPROOT.$sExtensionDir;
-		if (is_dir($sExtensionsPath)) {
-			// if the extensions dir exists, scan it for additional modules as well
-			$aDirsToScan[] = $sExtensionsPath;
-		}
-		$sExtraPath = APPROOT.'/data/'.$sEnvironment.'-modules/';
-		if (is_dir($sExtraPath)) {
-			// if the extra dir exists, scan it for additional modules as well
-			$aDirsToScan[] = $sExtraPath;
-		}
-		$sTargetPath = APPROOT.$sTargetDir;
-
-		if (!is_dir($sSourcePath)) {
-			throw new Exception("Failed to find the source directory '$sSourcePath', please check the rights of the web server");
-		}
-
-		$bIsAlreadyInMaintenanceMode = SetupUtils::IsInMaintenanceMode();
-
-		if (($sEnvironment == 'production') && !$bIsAlreadyInMaintenanceMode) {
-			$sConfigFilePath = utils::GetConfigFilePath($sEnvironment);
-			if (is_file($sConfigFilePath)) {
-				$oConfig = new Config($sConfigFilePath);
-				$oConfig->UpdateFromParams($aParamValues);
-				if ($bEnterMaintenanceMode) {
-					SetupUtils::EnterMaintenanceMode($oConfig);
-				}
-			}
-		}
-		try {
-			if (!is_dir($sTargetPath)) {
-				if (!mkdir($sTargetPath)) {
-					throw new Exception("Failed to create directory '$sTargetPath', please check the rights of the web server");
-				} else {
-					// adjust the rights if and only if the directory was just created
-					// owner:rwx user/group:rx
-					chmod($sTargetPath, 0755);
-				}
-			} elseif (substr($sTargetPath, 0, strlen(APPROOT)) == APPROOT) {
-				// If the directory is under the root folder - as expected - let's clean-it before compiling
-				SetupUtils::tidydir($sTargetPath);
-			}
-
-			$oExtensionsMap = new iTopExtensionsMap('production', $aDirsToScan);
-			$oExtensionsMap->DeclareExtensionAsRemoved($aRemovedExtensionCodes);
-
-			$oFactory = new ModelFactory($aDirsToScan);
-
-			$oDictModule = new MFDictModule('dictionaries', 'iTop Dictionaries', APPROOT.'dictionaries');
-			$oFactory->LoadModule($oDictModule);
-
-			$sDeltaFile = APPROOT.'core/datamodel.core.xml';
-			if (file_exists($sDeltaFile)) {
-				$oCoreModule = new MFCoreModule('core', 'Core Module', $sDeltaFile);
-				$oFactory->LoadModule($oCoreModule);
-			}
-			$sDeltaFile = APPROOT.'application/datamodel.application.xml';
-			if (file_exists($sDeltaFile)) {
-				$oApplicationModule = new MFCoreModule('application', 'Application Module', $sDeltaFile);
-				$oFactory->LoadModule($oApplicationModule);
-			}
-
-			$aModules = $oFactory->FindModules();
-
-			foreach ($aModules as $oModule) {
-				$sModule = $oModule->GetName();
-				if (in_array($sModule, $aSelectedModules)) {
-					$oFactory->LoadModule($oModule);
-				}
-			}
-			// Dump the "reference" model, just before loading any actual delta
-			$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$sEnvironment.'.xml');
-
-			$sDeltaFile = utils::GetDataPath().$sEnvironment.'.delta.xml';
-			if (file_exists($sDeltaFile)) {
-				$oDelta = new MFDeltaModule($sDeltaFile);
-				$oFactory->LoadModule($oDelta);
-				$oFactory->SaveToFile(utils::GetDataPath().'datamodel-'.$sEnvironment.'-with-delta.xml');
-			}
-
-			$oMFCompiler = new MFCompiler($oFactory, $sEnvironment);
-			$oMFCompiler->Compile($sTargetPath, null, $bUseSymbolicLinks, false, $bEnterMaintenanceMode);
-			//$aCompilerLog = $oMFCompiler->GetLog();
-			//SetupLog::Info(implode("\n", $aCompilerLog));
-			SetupLog::Info("Data model successfully compiled to '$sTargetPath'.");
-
-			$sCacheDir = APPROOT.'/data/cache-'.$sEnvironment.'/';
-			SetupUtils::builddir($sCacheDir);
-			SetupUtils::tidydir($sCacheDir);
-		} catch (Exception $e) {
-			if (($sEnvironment == 'production') && !$bIsAlreadyInMaintenanceMode) {
-				SetupUtils::ExitMaintenanceMode();
-			}
-			throw $e;
-		}
-
-		// 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);
-		}
-
-		// Set an "Instance UUID" identifying this machine based on a file located in the data directory
-		$sInstanceUUIDFile = utils::GetDataPath().'instance.txt';
-		SetupUtils::builddir(utils::GetDataPath());
-		if (!file_exists($sInstanceUUIDFile)) {
-			$sIntanceUUID = utils::CreateUUID('filesystem');
-			file_put_contents($sInstanceUUIDFile, $sIntanceUUID);
-		}
-		if (($sEnvironment == 'production') && !$bIsAlreadyInMaintenanceMode && $bEnterMaintenanceMode) {
-			SetupUtils::ExitMaintenanceMode();
-		}
-	}
-
 	protected function GetModelInfoPath(string $sEnv): string
 	{
 		return APPROOT."data/beforecompilation_".$sEnv."_modelinfo.json";
diff --git a/setup/sequencers/DataAuditSequencer.php b/setup/sequencers/DataAuditSequencer.php
index bea3bf0f8..1bc6fcfd0 100644
--- a/setup/sequencers/DataAuditSequencer.php
+++ b/setup/sequencers/DataAuditSequencer.php
@@ -25,9 +25,6 @@ require_once APPROOT.'setup/feature_removal/SetupAudit.php';
 require_once(APPROOT.'setup/sequencers/StepSequencer.php');
 require_once(APPROOT.'setup/sequencers/ApplicationInstallSequencer.php');
 
-use Combodo\iTop\Setup\FeatureRemoval\DryRemovalRuntimeEnvironment;
-use Combodo\iTop\Setup\FeatureRemoval\SetupAudit;
-
 class DataAuditSequencer extends ApplicationInstallSequencer
 {
 	public const DATA_AUDIT_FAILED = 100;
@@ -35,12 +32,14 @@ class DataAuditSequencer extends ApplicationInstallSequencer
 	protected function GetTempEnv()
 	{
 		$sTargetEnv = $this->GetTargetEnv();
+
 		return $sTargetEnv.'-build';
 	}
 
 	protected function GetTargetDir()
 	{
 		$sTargetEnv = $this->GetTempEnv();
+
 		return 'env-'.$sTargetEnv;
 	}
 
@@ -56,102 +55,56 @@ class DataAuditSequencer extends ApplicationInstallSequencer
 	public function ExecuteStep($sStep = '', $sInstallComment = null)
 	{
 		try {
+			/**
+			 * @since 3.2.0 move the ContextTag init at the very beginning of the method
+			 * @noinspection PhpUnusedLocalVariableInspection
+			 */
+			$oContextTag = new ContextTag(ContextTag::TAG_SETUP);
 			$fStart = microtime(true);
 			SetupLog::Info("##### STEP {$sStep} start");
 			switch ($sStep) {
 				case '':
-					$this->DoLogParameters('data-audit-', 'Data Audit');
+					return $this->GetNextStep('copy', 'Copying data model files', 5);
 
-					$aResult = [
-						'status' => self::OK,
-						'message' => '',
-						'percentage-completed' => 20,
-						'next-step' => 'compile',
-						'next-step-label' => 'Compiling the data model',
-					];
-
-					break;
+				case 'copy':
+					$this->oRunTimeEnvironment->CopySetupFiles();
+					return $this->GetNextStep('compile', 'Compiling the data model', 20, 'Copying...');
 
 				case 'compile':
 					$aSelectedModules = $this->oParams->Get('selected_modules');
 					$sSourceDir = $this->oParams->Get('source_dir', 'datamodels/latest');
 					$sExtensionDir = $this->oParams->Get('extensions_dir', 'extensions');
+					$aMiscOptions = $this->oParams->Get('options', []);
 					$aRemovedExtensionCodes = $this->oParams->Get('removed_extensions', []);
-
-					$this->DoCompile(
+					$bUseSymbolicLinks = $aMiscOptions['symlinks'] ?? false;
+					$sMessage = $bUseSymbolicLinks ? '' : 'Using symbolic links instead of copying data model files (for developers only!)';
+					$this->oRunTimeEnvironment->DoCompile(
 						$aRemovedExtensionCodes,
 						$aSelectedModules,
 						$sSourceDir,
 						$sExtensionDir,
-						false,
-						false
+						$bUseSymbolicLinks
 					);
+					return $this->GetNextStep('setup-audit', 'Checking data consistency with the new data model', 70, $sMessage);
 
-					$aResult = [
-						'status' => self::OK,
-						'message' => '',
-						'next-step' => 'write-config',
-						'next-step-label' => 'Writing audit config',
-						'percentage-completed' => 40,
-					];
-					break;
-				case 'write-config':
-					$this->DoWriteConfig();
-					$aResult = [
-						'status' => self::OK,
-						'message' => '',
-						'next-step' => 'setup-audit',
-						'next-step-label' => 'Checking data consistency with the new data model',
-						'percentage-completed' => 60,
-					];
-					break;
 				case 'setup-audit':
-					$this->DoSetupAudit();
-					$aResult = [
-						'status' => self::OK,
-						'message' => '',
-						'next-step' => 'cleanup',
-						'next-step-label' => 'Temporary folders cleanup',
-						'percentage-completed' => 80,
-					];
-					break;
-				case 'cleanup' :
-					$this->DoCleanup();
-					$aResult = [
-						'status' => self::OK,
-						'message' => '',
-						'next-step' => '',
-						'next-step-label' => 'Completed',
-						'percentage-completed' => 100,
-					];
-					break;
-				default:
-					$aResult = [
-						'status' => self::ERROR,
-						'message' => '',
-						'next-step' => '',
-						'next-step-label' => "Unknown setup step '$sStep'.",
-						'percentage-completed' => 100,
-					];
-					break;
-			}
-		} catch (Exception $e) {
-			$aResult = [
-				'status' => self::ERROR,
-				'message' => $e->getMessage(),
-				'next-step' => '',
-				'next-step-label' => '',
-				'percentage-completed' => 100,
-				'error_code' => $e->getCode(),
-			];
+					$this->oRunTimeEnvironment->DataToCleanupAudit();
+					return $this->GetNextStep('', 'Completed', 100);
 
+				default:
+					return $this->GetNextStep('', "Unknown setup step '$sStep'.", 100, '', self::ERROR);
+			}
+		}
+		catch (Exception $e) {
 			$this->ReportException($e);
-		} finally {
+			$aResult = $this->GetNextStep('', '', 100, $e->getMessage(), self::ERROR);
+			$aResult['error_code'] = $e->getCode();
+			return $aResult;
+		}
+		finally {
 			$fDuration = round(microtime(true) - $fStart, 2);
 			SetupLog::Info("##### STEP {$sStep} duration: {$fDuration}s");
 		}
-
-		return $aResult;
 	}
 
 	protected function DoWriteConfig()
@@ -167,57 +120,7 @@ class DataAuditSequencer extends ApplicationInstallSequencer
 
 			return $oConfig->WriteToFile($sTempConfigFileName);
 		}
+
 		return false;
 	}
-
-	protected function DoSetupAudit()
-	{
-		/**
-		 * @since 3.2.0 move the ContextTag init at the very beginning of the method
-		 * @noinspection PhpUnusedLocalVariableInspection
-		 */
-		$oContextTag = new ContextTag(ContextTag::TAG_SETUP);
-
-		$sPreviousEnvironment = $this->GetTargetEnv();
-
-		$oSetupAudit = new SetupAudit($sPreviousEnvironment);
-
-		//Make sure the MetaModel is started before analysing for issues
-		$sConfFile = utils::GetConfigFilePath($sPreviousEnvironment);
-		MetaModel::Startup($sConfFile, false /* $bModelOnly */, false /* $bAllowCache */, false /* $bTraceSourceFiles */, $sPreviousEnvironment);
-		$oSetupAudit->GetIssues(true);
-		$iCount = $oSetupAudit->GetDataToCleanupCount();
-
-		if ($iCount > 0) {
-			throw new Exception("$iCount elements require data adjustments or cleanup in the backoffice prior to upgrading iTop", static::DATA_AUDIT_FAILED);
-		}
-	}
-
-	protected function DoCleanup()
-	{
-		$sEnv = $this->GetTempEnv();
-
-		//keep this folder empty
-		SetupUtils::tidydir(APPROOT."/env-$sEnv");
-
-		$aFolders = [
-			APPROOT."/data/$sEnv-modules",
-			APPROOT."/data/cache-$sEnv",
-			APPROOT."/conf/$sEnv",
-		];
-		foreach ($aFolders as $sFolder) {
-			SetupUtils::tidydir($sFolder);
-			SetupUtils::rmdir_safe($sFolder);
-		}
-
-		$sFiles = [
-			APPROOT."/data/datamodel-$sEnv.xml",
-			APPROOT."/data/$sEnv.delta.prev.xml",
-		];
-		foreach ($sFiles as $sFile) {
-			if (is_file($sFile)) {
-				@unlink($sFile);
-			}
-		}
-	}
 }
diff --git a/setup/sequencers/StepSequencer.php b/setup/sequencers/StepSequencer.php
index ca9f83d08..53f72666f 100644
--- a/setup/sequencers/StepSequencer.php
+++ b/setup/sequencers/StepSequencer.php
@@ -102,5 +102,37 @@ abstract class StepSequencer
 		return ($iOverallStatus == self::OK);
 	}
 
+	protected function GetNextStep(string $sNextStep, string $sNextStepLabel, int $iPercentComplete, string $sMessage = '', int $iStatus = self::OK): array
+	{
+		return [
+			'status' => $iStatus,
+			'message' => $sMessage,
+			'next-step' => $sNextStep,
+			'next-step-label' => $sNextStepLabel,
+			'percentage-completed' => $iPercentComplete,
+		];
+	}
+
+	protected function DoLogParameters($sPrefix = 'install-', $sOperation = 'Installation')
+	{
+		// Log the parameters...
+		$oDoc = new DOMDocument('1.0', 'UTF-8');
+		$oDoc->preserveWhiteSpace = false;
+		$oDoc->formatOutput = true;
+		$this->oParams->ToXML($oDoc, null, 'installation');
+		$sXML = $oDoc->saveXML();
+		$sSafeXml = preg_replace('|<pwd>([^<]*)</pwd>|', '<pwd>**removed**</pwd>', $sXML);
+		SetupLog::Info('======= '.$sOperation." starts =======\nParameters:\n$sSafeXml\n");
+
+		// Save the response file as a stand-alone file as well
+		$sFileName = $sPrefix.date('Y-m-d');
+		$index = 0;
+		while (file_exists(APPROOT.'log/'.$sFileName.'.xml')) {
+			$index++;
+			$sFileName = $sPrefix.date('Y-m-d').'-'.$index;
+		}
+		file_put_contents(APPROOT.'log/'.$sFileName.'.xml', $sSafeXml);
+	}
+
 	abstract public function ExecuteStep($sStep = '', $sComment = null);
 }
diff --git a/setup/setuputils.class.inc.php b/setup/setuputils.class.inc.php
index 60b2fa43f..f10f8532a 100644
--- a/setup/setuputils.class.inc.php
+++ b/setup/setuputils.class.inc.php
@@ -817,6 +817,11 @@ class SetupUtils
 		}
 	}
 
+	public static function CopyFile(string $sSource, string $sDest, bool $bUseSymbolicLinks = false): bool
+	{
+		return self::copydir($sSource, $sDest, $bUseSymbolicLinks);
+	}
+
 	/**
 	 * Helper to copy a directory to a target directory, skipping .SVN files (for developer's comfort!)
 	 * Returns true if successful
@@ -826,11 +831,13 @@ class SetupUtils
 	 * @return bool
 	 * @throws Exception
 	 */
-	public static function copydir($sSource, $sDest, $bUseSymbolicLinks = false)
+	public static function copydir(string $sSource, string $sDest, bool $bUseSymbolicLinks = false): bool
 	{
 		if (is_dir($sSource)) {
 			if (!is_dir($sDest)) {
 				mkdir($sDest, 0777 /* Default */, true);
+			} else {
+				SetupUtils::tidydir($sDest);
 			}
 			$aFiles = scandir($sSource);
 			if (sizeof($aFiles) > 0) {
@@ -839,24 +846,13 @@ class SetupUtils
 						// Skip
 						continue;
 					}
-
 					if (is_dir($sSource.'/'.$sFile)) {
 						// Recurse
 						self::copydir($sSource.'/'.$sFile, $sDest.'/'.$sFile, $bUseSymbolicLinks);
 					} else {
 						if ($bUseSymbolicLinks) {
-							if (function_exists('symlink')) {
-								if (file_exists($sDest.'/'.$sFile)) {
-									unlink($sDest.'/'.$sFile);
-								}
-								symlink($sSource.'/'.$sFile, $sDest.'/'.$sFile);
-							} else {
-								throw(new Exception("Error, cannot *copy* '$sSource/$sFile' to '$sDest/$sFile' using symbolic links, 'symlink' is not supported on this system."));
-							}
+							symlink($sSource.'/'.$sFile, $sDest.'/'.$sFile);
 						} else {
-							if (is_link($sDest.'/'.$sFile)) {
-								unlink($sDest.'/'.$sFile);
-							}
 							copy($sSource.'/'.$sFile, $sDest.'/'.$sFile);
 						}
 					}
@@ -865,11 +861,7 @@ class SetupUtils
 			return true;
 		} elseif (is_file($sSource)) {
 			if ($bUseSymbolicLinks) {
-				if (function_exists('symlink')) {
-					return symlink($sSource, $sDest);
-				} else {
-					throw(new Exception("Error, cannot *copy* '$sSource' to '$sDest' using symbolic links, 'symlink' is not supported on this system."));
-				}
+				return symlink($sSource, $sDest);
 			} else {
 				return copy($sSource, $sDest);
 			}
diff --git a/setup/wizardsteps/AbstractWizStepInstall.php b/setup/wizardsteps/AbstractWizStepInstall.php
index e422a4359..febc309e2 100644
--- a/setup/wizardsteps/AbstractWizStepInstall.php
+++ b/setup/wizardsteps/AbstractWizStepInstall.php
@@ -67,6 +67,10 @@ abstract class AbstractWizStepInstall extends WizardStep
 				'copies' => $aCopies,
 				// 'backup' => see below
 			],
+			'optional_steps' => [
+				''
+				// '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,