Owncloud upgrade trouble

update_issue
upgrade

#1

After performing an update of owncloud-files (that went smoothly btw) I was prompted to run "php occ upgrade".
I did, following appeared:

www-data@oc:~/owncloud$ php occ upgrade
ownCloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade
An unhandled exception has been thrown:
Exception: DateTimeZone::__construct(): Unknown or bad timezone (UTC+1) in /var/www/owncloud/lib/private/Console/TimestampFormatter.php:100
Stack trace:
#0 /var/www/owncloud/lib/private/Console/TimestampFormatter.php(100): DateTimeZone->__construct('UTC+1')
#1 /var/www/owncloud/lib/composer/symfony/console/Output/Output.php(157): OC\Console\TimestampFormatter->format('')
#2 /var/www/owncloud/lib/composer/symfony/console/Output/Output.php(134): Symfony\Component\Console\Output\Output->write(Array, true, 16)
#3 /var/www/owncloud/lib/composer/symfony/console/Application.php(621): Symfony\Component\Console\Output\Output->writeln('', 16)
#4 /var/www/owncloud/lib/composer/symfony/console/Application.php(127): Symfony\Component\Console\Application->renderException(Object(Exception), Object(Symfony\Component\Console\Output\StreamOutput))
#5 /var/www/owncloud/lib/private/Console/Application.php(160): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#6 /var/www/owncloud/console.php(106): OC\Console\Application->run()
#7 /var/www/owncloud/occ(11): require_once('/var/www/ownclo...')

How should I proceed after this?

Loaded apps:

Enabled:
  - announcementcenter: 1.2.0
  - comments: 0.3.0
  - configreport: 0.1.1
  - customgroups: 0.3.1
  - dav: 0.2.9
  - external: 1.2
  - federatedfilesharing: 0.3.0
  - federation: 0.1.0
  - files: 1.5.1
  - files_antivirus: 0.10.0.0
  - files_external: 0.7.0
  - files_sharing: 0.10.0
  - files_trashbin: 0.9.0
  - files_versions: 1.3.0
  - files_videoplayer: 0.9.8
  - firstrunwizard: 1.1
  - market: 0.2.1
  - notifications: 0.3.0
  - provisioning_api: 0.5.0
  - richdocuments: 1.1.23
  - systemtags: 0.3.0
  - templateeditor: 0.1
  - updatenotification: 0.2.1
  - user_external: 0.4
  - user_ldap: 0.9.1
Disabled:
  - encryption
  - theme-example

#2
    public function format($message) {

            $timeZone = $this->config->getSystemValue('logtimezone', null);
            $timeZone = $timeZone !== null ? new \DateTimeZone($timeZone) : null;

#3

Solution:

Changing
'logtimezone' => 'UTC+1',
To
'logtimezone' => 'Europe/Berlin',