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.
No. Actually the base table structure was modified and I would like to add the new fields to my Fabrik list. When you say "sync", what do you mean? I couldn't find this anywhere in the Fabrik admin.
Thanks again!