I've been getting this error for a while now:
Error: Call to undefined method IPS\core\extensions\core\AdminNotifications\NewRegComplete::member() (0)
#0 /home//public_html/system/Email/Email.php(1051): IPS\Theme\email__core_acp_notification_NewRegComplete_subject_pt_BR_UTF_8(Object(IPS\core\extensions\core\AdminNotifications\NewRegComplete), Object(IPS\Member), Object(IPS\Email\Outgoing\Php))
#1 /home//public_html/system/Email/Email.php(540): IPS\_Email::devProcessTemplate('email__core_acp...', '{$notification-...', Array, 'plaintext')
#2 /home//public_html/system/Email/Outgoing/Php.php(46): IPS\_Email->compileSubject(Object(IPS\Member))
#3 /home//public_html/system/Email/Email.php(732): IPS\Email\Outgoing\_PHP->_send(Object(IPS\Member), Array, Array, NULL, NULL, Array)
#4 /home//public_html/applications/core/sources/AdminNotification/AdminNotification.php(355): IPS\_Email->send(Object(IPS\Member))
#5 /home//public_html/system/Member/Member.php(4565): IPS\core\_AdminNotification::send('core', 'NewRegComplete', NULL, true, Object(IPS\Member), Object(IPS\Member))
#6 /home//public_html/applications/core/modules/admin/members/members.php(2572): IPS\_Member->validationComplete(Object(IPS\Member))
#7 /home//public_html/system/Dispatcher/Controller.php(90): IPS\core\modules\admin\members\_members->approve()
#8 /home//public_html/system/Dispatcher/Dispatcher.php(153): IPS\Dispatcher\_Controller->execute()
#9 /home//public_html/_adm/index.php(13): IPS\_Dispatcher->run()
#10 {main}
No idea how to solve it.