Test 1 Do a grep for 'print_textarea' ( grep -Ri print_textarea * ) Confirm that the only results are in: lib/deprecatedlib.php (the deprecated function) lib/upgrade.txt (the notes about the deprecated function) lib/outputrenderers.php (Not really a match, just looks like one) Note: Uses of $OUTPUT->print_textarea are fine. Test 2 Put the following code into a file test_form.php in your wwwroot. <?php   require_once ( 'config.php' ); require_once ( $CFG ->libdir. '/formslib.php' );   $PAGE ->set_context(context_system::instance()); $PAGE ->set_url( $CFG ->wwwroot . '/test_form.php' );   class test_form extends moodleform {   public function definition() { $mform =& $this ->_form; $mform ->addElement( 'header' , 'general' , get_string( 'general' , 'form' )); $mform ->addElement( 'htmleditor' , 'htmleditor' ); $mform ->addElement( 'editor' , 'editor' ); } }   $form = new test_form(); echo $OUTPUT ->header(); echo $form ->display(); echo $OUTPUT ->footer(); Visit <yoursite>/test_form.php and ensure there are two textareas displayed (second one larger than the first). Test 3 Create a course. Enrol a student. Log in as the student. Click on the 'Notification' icon in the top-right then on the cog. Turn on all the 'Feedback' notifications (all 4 checkboxes should be green) Log in as the admin. Visit the course with the enrolled student. Add a feedback activity with 'Record user names' set to "User's name will be logged and shown with answers". Click on the feedback activity. Click on the 'Show non-respondents' tab. Select the checkbox next to the user. Write a subject and message. Click 'Send'. Log in as the student and confirm there is a notification with the subject listed in the pop-up. Click on 'View full notification'. Confirm the message is shown on the next page Test 4 Add the following code to test_deprecation.php in your wwwroot. <?php   require_once ( 'config.php' );   $deprecatedstrings =[ 'formattexttype' => 'core' , 'currentlyselectedusers' => 'core' , 'emailuserhasnone' => 'core' , 'emaildisplayhidden' => 'core' , 'sitemessage' => 'core' , 'coursemessage' => 'core' , 'addedrecip' => 'core' , 'addedrecips' => 'core' , 'messagingdisabled' => 'core_message' , 'messagedselectedcountusersfailed' => 'core' , 'backtoparticipants' => 'core' , 'keepsearching' => 'core' , 'allfieldsrequired' => 'core' , 'previewhtml' => 'core' , 'messagedselecteduserfailed' => 'core' , ];   foreach ( $deprecatedstrings as $string => $component ) { print_string( $string , $component ); } Visit the page. Confirm there are 15 debugging notices warning about deprecated strings. Test 5 Create a course. Add a wiki activity. Click on the wiki. Select the 'NWiki' format for the first page and save. Click on the 'Comments' tab. Click 'Add comment'. Ensure there is no debugging message. Confirm you can add a comment