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.
{"opt":{"cmd":"_xclick-subscriptions","business":"xxxxxx-facilitator@gmail.com","shipping":"","item_name":"Apple Pie Subscription","p3":"1","t3":"Y","a3":"20.00","no_note":1,"custom":"28:57:","invoice":"568f59db8a3ff0.00565586","src":"1","currency_code":"USD","notify_url":"..."},"data":{...}}
$sub = $subDb->loadObject();
// Log the query
$this->doLog('fabrik.paypal.onAfterProcess.debug', "Subscription query: " . (string)$query);