For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
As far as I know Greek letters '????????' is not '????????' (should be ????????, in this case it's working on my site)
Hello
I think the cdd issue was resolved last week