import logging

		#######################################################################

		# APP UPDATE

		#######################################################################

		try:

			from univention.appcenter.actions import get_action

			import univention.appcenter.log as appcenter_log

			from argparse import Namespace

			app_upgrade = get_action('upgrade')

			if app_upgrade is None:

				raise ImportError()

		except ImportError:

			# the new univention.appcenter package is not installed. nevermind

			# cannot be a dependency as the app center depends on updater...

			pass

		else:

			# check if component updates are available

			dprint(silent, 'Checking for app updates: ', newline=False)

			app_upgrade = app_upgrade()

			appcenter_log.log_to_logfile()

			appcenter_log._reverse_umc_module_logger()

			# own logging

			handler = logging.FileHandler(LOGFN)

			appcenter_log.get_base_logger().addHandler(handler)

			logger = logging.getLogger('univention.appcenter.actions.upgrade.readme')

			handler = logging.StreamHandler(sys.stdout)

			handler.setLevel(logging.INFO)

			logger.addHandler(handler)

			new_apps = list(app_upgrade.iter_upgradable_apps())

			update_available = bool(new_apps)

			if update_available:

				# updates available ==> stop here in "check-mode"

				if checkForUpdates:

					dprint(silent, 'found')

					return True

				dprint(silent, 'found\n')

				dprint(silent, 'The following apps can be updated:\n')

				for app in new_apps:

					dprint(silent, '%(name)s: Version %(old)s can be updated to %(new)s' % {'name': app.name, 'old': app.version, 'new': app.candidate.version})

				dprint(silent, 'Starting univention-app update at %s...' % (time.ctime()), debug=True)

				dprint(silent, '\nStarting app update', newline=False)

				success = True

				for app in new_apps:

					if interactive:

						run_app = readcontinue('\nDo you want to update %s [Y|n]?' % app.name)

					if run_app:

						time.sleep(1)

						success = app_upgrade.call(app=app, noninteractive=not interactive) and success

				if not success:

					dprint(silent, 'ERROR: app upgrade failed. Please check /var/log/univention/updater.log\n')

					sys.exit(1)

				dprint(silent, 'univention-app upgrade finished at %s...' % (time.ctime()), debug=True)

				dprint(silent, 'done')

				time.sleep(1)

			else:

				dprint(silent, 'none')