diff --git a/SSO.php b/SSO.php
index a6ac3f6..e0acf77 100644
--- a/SSO.php
+++ b/SSO.php
@@ -136,7 +136,7 @@
         $responseparamsencoded =
             'serverName=' . $servername . '&externalUserKey=' . urlencode($userkey) . '&expiration=' . $expiration;
 
-        $fullreturnurl = !empty($returnurl) ? '&ReturnUrl=' . $returnurl . $fragment : "";
+        $fullreturnurl = !empty($returnurl) ? '&ReturnUrl=' . urlencode($returnurl) . $fragment : "";
         $separator = (strpos($url, '?') ? '&' : '?');
         $redirecturl = $url . $separator . $responseparamsencoded . '&authCode=' . $responseauthcode . $fullreturnurl;
 
diff --git a/block_panopto.php b/block_panopto.php
index 3b194ae..10fa0b2 100644
--- a/block_panopto.php
+++ b/block_panopto.php
@@ -162,7 +162,7 @@ public function get_content() {
                                     null,
                                     true);
 
-        $this->content->text  = html_writer::tag('div', "<font id='loading_text'>" .
+        $this->content->text = html_writer::tag('div', "<font id='loading_text'>" .
             get_string('fetching_content', 'block_panopto') . '</font>', $params);
 
         $this->content->text .= '<script type="text/javascript">' .
diff --git a/lib/lti/auth.php b/lib/lti/auth.php
index 44fe03e..077d12a 100644
--- a/lib/lti/auth.php
+++ b/lib/lti/auth.php
@@ -51,13 +51,29 @@
 $clientid = optional_param('client_id', '', PARAM_TEXT);
 $redirecturi = optional_param('redirect_uri', '', PARAM_URL);
 $loginhint = optional_param('login_hint', '', PARAM_TEXT);
-$ltimessagehint = optional_param('lti_message_hint', '', PARAM_TEXT);
+$ltimessagehintenc = optional_param('lti_message_hint', '', PARAM_TEXT);
 $state = optional_param('state', '', PARAM_TEXT);
 $responsemode = optional_param('response_mode', '', PARAM_TEXT);
 $nonce = optional_param('nonce', '', PARAM_TEXT);
 $prompt = optional_param('prompt', '', PARAM_TEXT);
 
-list($pluginname, $callback, $toolid, $resourcelinkid, $contenturl, $customdata) = explode(',', $ltimessagehint, 6);
+// Specific logic for Moodle 4.1 needed, in order to handle auth.
+$isthismoodle41 = empty($CFG->version) ? false : $CFG->version >= 2022112800.00;
+$ltimessagehint = $isthismoodle41 ? json_decode($ltimessagehintenc) : $ltimessagehintenc;
+
+list(
+    $pluginname,
+    $callback,
+    $toolid,
+    $resourcelinkid,
+    $contenturl,
+    $customdata
+) = explode(
+    ',',
+    $isthismoodle41 ? $ltimessagehint->cmid : $ltimessagehint,
+    6
+);
+
 $ispanoptoplugin = false;
 $pluginpath = '';
 switch($pluginname)
@@ -90,17 +106,25 @@
                 '&nonce=' . urlencode($nonce) .
                 "&login_hint=$loginhint" .
                 "&prompt=$prompt" .
-                "&lti_message_hint=$ltimessagehint"
+                "&lti_message_hint=$ltimessagehintenc"
             );
 }
 
 $ok = !empty($scope) && !empty($responsetype) && !empty($clientid) &&
       !empty($redirecturi) && !empty($loginhint) &&
-      !empty($nonce) && !empty($SESSION->lti_message_hint);
+      !empty($nonce) && ($isthismoodle41 ? true : !empty($SESSION->lti_message_hint));
 
 if (!$ok) {
     $error = 'invalid_request';
 }
+// This is only Moodle 4.1 check.
+if ($isthismoodle41) {
+    $ok = $ok && isset($ltimessagehint->launchid);
+    if (!$ok) {
+        $error = 'invalid_request';
+        $desc = 'No launch id in LTI hint';
+    }
+}
 if ($ok && ($scope !== 'openid')) {
     $ok = false;
     $error = 'invalid_scope';
@@ -110,17 +134,18 @@
     $error = 'unsupported_response_type';
 }
 if ($ok) {
-    list($courseid, $typeid, $id, $titleb64, $textb64) = explode(',', $SESSION->lti_message_hint, 5);
+    if ($isthismoodle41) {
+        $launchid = $ltimessagehint->launchid;
+        list($courseid, $typeid, $id, $messagetype, $foruserid, $titleb64, $textb64) = explode(',', $SESSION->$launchid, 7);
+        unset($SESSION->$launchid);
+    } else {
+        list($courseid, $typeid, $id, $titleb64, $textb64) = explode(',', $SESSION->lti_message_hint, 5);
+    }
 
-    $ok = true;
+    $config = lti_get_type_type_config($typeid);
+    $ok = ($clientid === $config->lti_clientid);
     if (!$ok) {
-        $error = 'invalid_request';
-    } else {
-        $config = lti_get_type_type_config($typeid);
-        $ok = ($clientid === $config->lti_clientid);
-        if (!$ok) {
-            $error = 'unauthorized_client';
-        }
+        $error = 'unauthorized_client';
     }
 }
 if ($ok && ($loginhint !== $USER->id)) {
@@ -146,7 +171,7 @@
     throw new moodle_exception('invalidrequest', 'error');
 } else {
     $uris = array_map("trim", explode("\n", $config->lti_redirectionuris));
-    if (!in_array($redirecturi, $uris)) {
+    if (!in_array(strtolower($redirecturi), array_map("strtolower", $uris))) {
         throw new moodle_exception('invalidrequest', 'error');
     }
 }
diff --git a/lib/lti/panoptoblock_lti_utility.php b/lib/lti/panoptoblock_lti_utility.php
index 95f9fd1..d7a4748 100644
--- a/lib/lti/panoptoblock_lti_utility.php
+++ b/lib/lti/panoptoblock_lti_utility.php
@@ -497,9 +497,10 @@ public static function get_course_tool($courseid) {
      * @throws moodle_exception When the LTI tool type does not exist.`
      * @throws coding_exception For invalid media type and presentation target parameters.
      */
-    public static function build_content_item_selection_request($id, $course, moodle_url $returnurl, $title = '', $text = '', $mediatypes = [],
-                                                      $presentationtargets = [], $autocreate = false, $multiple = true,
-                                                      $unsigned = false, $canconfirm = false, $copyadvice = false, $nonce = '', $pluginname = '') {
+    public static function build_content_item_selection_request($id, $course, moodle_url $returnurl, $title = '', $text = '',
+                                                      $mediatypes = [], $presentationtargets = [], $autocreate = false,
+                                                      $multiple = true, $unsigned = false, $canconfirm = false,
+                                                      $copyadvice = false, $nonce = '', $pluginname = '') {
         global $USER, $CFG;
         require_once($CFG->dirroot . '/mod/lti/locallib.php');
 
diff --git a/version.php b/version.php
index aca81ef..db931d9 100644
--- a/version.php
+++ b/version.php
@@ -29,10 +29,10 @@
 
 // Plugin version should normally be the same as the internal version.
 // If an admin wants to install with an older version number, however, set that here.
-$plugin->version = 2023012400;
+$plugin->version = 2023031400;
 
 // Requires this Moodle version - 2.7.
-$plugin->requires  = 2014051200;
+$plugin->requires = 2014051200;
 $plugin->cron = 0;
 $plugin->component = 'block_panopto';
 $plugin->maturity = MATURITY_STABLE;