PHP 7.1 Error with User Search

When we update our site to PHP 7.1 and it breaks our search option in the wp-admin/users. It goes to a 500error can not process.

Below are the errors we receive.

It looks like the following syntax error is responsible for the 500 error that you’re seeing:

[25-Apr-2018 13:22:05 UTC] PHP Fatal error: Uncaught TypeError: Argument 1 passed to Ai1ec_Exception_Handler::_get_backtrace() must be an instance of Exception, instance of Error given, called in /www/wp-content/plugins/all-in-one-event-calendar/lib/exception/handler.php on line 199 and defined in /www/wp-content/plugins/all-in-one-event-calendar/lib/exception/handler.php:570

Stack trace:
#0 /www/wp-content/plugins/all-in-one-event-calendar/lib/exception/handler.php(199): Ai1ec_Exception_Handler->_get_backtrace(Object(Error))

#1 [internal function]: Ai1ec_Exception_Handler->handle_exception(Object(Error))

#2 {main}
thrown in /www/wp-content/plugins/all-in-one-event-calendar/lib/exception/handler.php on line 570

So we have to roll the site back to the previous PHP version.