To update previous post about problems described above:

I've moved ....una/modules/boonex/messenger to ...una/modules/boonex/messenger-new and copied previous version from my backup to ....una/modules/boonex/messenger

And problems disappears.

So there are problems related to new version 12.0.3 of messenger not something else....

I also had to change cron job from:

/usr/bin/php8.0 -q ..../una/periodic/cron.php

to

/usr/bin/php7.4 -q ..../una/periodic/cron.php

because of this problem:

PHP Deprecated: Required parameter $iProfileId follows optional parameter $iLotId in .../una/modules/boonex/messenger/classes/BxMessengerTemplate.php on line 1031

This is very trivial and temporary solution ....