Error: Class "OCP\App" not found

Hello,
I set my clamav in antivirus app to delete infected files. It tries to delete it but it can’t. I get following error in logs

Error: Class "OCP\App" not found
/var/www/nextcloud/apps/files_antivirus/lib/Item.php - line 127:

OCA\Files_Antivirus\Item->deleteFile()

/var/www/nextcloud/apps/files_antivirus/lib/Status.php - line 168:

OCA\Files_Antivirus\Item->processInfected()

/var/www/nextcloud/apps/files_antivirus/lib/BackgroundJob/BackgroundScanner.php - line 327:

OCA\Files_Antivirus\Status->dispatch()

/var/www/nextcloud/apps/files_antivirus/lib/BackgroundJob/BackgroundScanner.php - line 123:

OCA\Files_Antivirus\BackgroundJob\BackgroundScanner->scanOneFile()

/var/www/nextcloud/lib/private/BackgroundJob/Job.php - line 54:

OCA\Files_Antivirus\BackgroundJob\BackgroundScanner->run()

/var/www/nextcloud/lib/private/BackgroundJob/TimedJob.php - line 60:

OC\BackgroundJob\Job->execute()

/var/www/nextcloud/cron.php - line 152:

OC\BackgroundJob\TimedJob->execute()

How can I fix this? is it a bug?