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
See Announcement
We have resolved the issue with the J! updater and this will be fixed in the next release.
$group_id = $formModel->getElementData('___groupid', true);
$time = $formModel->getElementData('___time', true);
$db = JFactory::getDbo();
$query = $db->getQuery(true);
$query->update('yourtable')->set('start_time = ' . $db->quote($time))->where('groupid = ' . $db_quote($group_id));
$db->setQuery($query);
$db->execute();