Error: Using $this when not in object context in /var/owncloud/apps-external/files_antivirus/lib/Cron/Task.php:110

[DeepDiver1975]

          > You can try to patch your installation with #554 and let us know if the issue has been fixed - THX

I may have missed something but :

An unhandled exception has been thrown:
Error: Using $this when not in object context in /var/owncloud/apps-external/files_antivirus/lib/Cron/Task.php:110
Stack trace:
#0 /var/owncloud/lib/private/BackgroundJob/Legacy/RegularJob.php(31): OCA\Files_Antivirus\Cron\Task::run()
#1 /var/owncloud/lib/private/BackgroundJob/Job.php(81): OC\BackgroundJob\Legacy\RegularJob->run()
#2 /var/owncloud/core/Command/System/Cron.php(126): OC\BackgroundJob\Job->execute()
#3 /var/owncloud/lib/composer/symfony/console/Command/Command.php(298): OC\Core\Command\System\Cron->execute()
#4 /var/owncloud/lib/composer/symfony/console/Application.php(1040): Symfony\Component\Console\Command\Command->run()
#5 /var/owncloud/lib/composer/symfony/console/Application.php(301): Symfony\Component\Console\Application->doRunCommand()
#6 /var/owncloud/lib/composer/symfony/console/Application.php(171): Symfony\Component\Console\Application->doRun()
#7 /var/owncloud/lib/private/Console/Application.php(165): Symfony\Component\Console\Application->run()
#8 /var/owncloud/console.php(116): OC\Console\Application->run()
#9 /var/owncloud/occ(11): require_once('/var/owncloud/c...')
#10 {main}

Originally posted by @CyberFred-CP in #378 (comment)