diff --git a/serendipity_event_google_analytics/serendipity_event_google_analytics.php b/serendipity_event_google_analytics/serendipity_event_google_analytics.php
index c27596733..d30a18098 100644
--- a/serendipity_event_google_analytics/serendipity_event_google_analytics.php
+++ b/serendipity_event_google_analytics/serendipity_event_google_analytics.php
@@ -8,6 +8,7 @@
 class serendipity_event_google_analytics extends serendipity_event
 {
     var $title = PLUGIN_EVENT_GOOGLE_ANALYTICS_NAME;
+    protected $markup_elements = array();
 
     // Docs:
     // - Install Google Tag Manager for web pages: https://developers.google.com/tag-platform/tag-manager/web
@@ -154,7 +155,7 @@ function gtag() {
                         !$markupDisabledConfig && !$markupDisabledPost) {
                         $element = $element['element'];
                         $eventData[$element] = preg_replace_callback(
-                            "#<a (.*)href=(\"|')(http://|https://|)([^\"']+)(\"|')([^>]*)>#isUm",
+                            "#<a\\s+(.*)href\\s*=\\s*[\"|'](http://|https://|)([^\"']*)[\"|']([^>]*)>#isUm",
                             array($this, 'analytics_tracker_callback'),
                             $eventData[$element]
                         );
@@ -162,21 +163,32 @@ function gtag() {
                 }
                 return true;
 
-            default :
+            default:
                 return false;
         } // end switch ($event) {
     }
 
+    /**
+     * matches:
+     * 0 = entire regexp match
+     * 1 = anything between "<a" and "href"
+     * 2 = scheme
+     * 3 = address
+     * 4 = anything after "href" and ">"
+     */
     function analytics_tracker_callback($matches)
     {
-        $parsed_url = parse_url($matches[3].$matches[4]);
+        $parsed_url = parse_url($matches[2].$matches[3]);
+
+        // Skip tracking for local URLs without scheme, or unknown scheme.
         if (!isset($parsed_url["scheme"]))
-            return;
+            return $matches[0];
         if (!in_array($parsed_url["scheme"], array("http", "https")))
-            return;
+            return $matches[0];
 
+        // Note: Assume, there is no second onclick-event in substr($matches[0], 2)
         return '<a onclick="_gaq.push([\'_trackPageview\', \'/extlink/' .
-            (function_exists('serendipity_specialchars') ? serendipity_specialchars($matches[4]) : htmlspecialchars($matches[4], ENT_COMPAT, LANG_CHARSET)) .
+            (function_exists('serendipity_specialchars') ? serendipity_specialchars($matches[3]) : htmlspecialchars($matches[3], ENT_COMPAT, LANG_CHARSET)) .
             '\']);" ' . substr($matches[0], 2);
     }
 
diff --git a/serendipity_event_google_sitemap/serendipity_event_google_sitemap.php b/serendipity_event_google_sitemap/serendipity_event_google_sitemap.php
index 49433a01f..461a8046a 100644
--- a/serendipity_event_google_sitemap/serendipity_event_google_sitemap.php
+++ b/serendipity_event_google_sitemap/serendipity_event_google_sitemap.php
@@ -308,7 +308,7 @@ function add_entries(&$sitemap_xml, $limit = 0) {
 
             // add entries
             foreach($entries as $entry) {
-                $max = max($entry['timestamp_1']+0, $entry['timestamp_2']+0);
+                $max = max(intval($entry['timestamp_1']), intval($entry['timestamp_2']));
                 $url = serendipity_archiveURL($entry['id'], $entry['title']);
                 $props = serendipity_fetchEntryProperties($entry['id']);                
                 $props['title'] = $entry['title'];
diff --git a/serendipity_event_userprofiles/serendipity_event_userprofiles.php b/serendipity_event_userprofiles/serendipity_event_userprofiles.php
index d8beef57b..edfa1a974 100755
--- a/serendipity_event_userprofiles/serendipity_event_userprofiles.php
+++ b/serendipity_event_userprofiles/serendipity_event_userprofiles.php
@@ -169,7 +169,7 @@ function introspect_config_item($name, &$propbag)
     }
 
     function &getLocalProperties() {
-        return array(
+        $props = array(
             'realname' => array('desc' => USERCONF_REALNAME,
                                 'type' => 'string'),
             'username' => array('desc' => USERCONF_USERNAME,
@@ -177,6 +177,7 @@ function &getLocalProperties() {
             'email'    => array('desc' => USERCONF_EMAIL,
                                 'type' => 'string')
         );
+        return $props;
     }
 
     function getShow($type, $user) {
@@ -315,7 +316,7 @@ function show() {
     function selected() {
         global $serendipity;
 
-        if ($serendipity['GET']['subpage'] == 'userprofiles') {
+        if (isset($serendipity['GET']['subpage']) && $serendipity['GET']['subpage'] == 'userprofiles') {
             return true;
         }
 
@@ -417,7 +418,7 @@ function editUser(&$user) {
                 $this->updateConfigVar($property, $profile, $user[$property], $user['authorid']);
                 $profile[$property] = $user[$property];
             } else {
-                $user[$property] = $profile[$property];
+                $user[$property] = $profile[$property] ?? null;
             }
 
             $this->showCol($property, $info, $user);
@@ -442,7 +443,7 @@ function editOptions(&$user) {
                 $this->updateConfigVar($property, $profile, $user[$property], $user['authorid']);
                 $profile[$property] = $user[$property];
             } else {
-                $user[$property] = $profile[$property];
+                $user[$property] = $profile[$property] ?? null;
             }
 
             $this->showCol($property, $info, $user);
@@ -538,12 +539,19 @@ function event_hook($event, &$bag, &$eventData, $addData = null) {
                         if (!$tfile) {
                             $tfile = dirname(__FILE__) . '/plugin_userprofile.tpl';
                         }
-                        $inclusion = $serendipity['smarty']->security_settings['INCLUDE_ANY'];
-                        $serendipity['smarty']->security_settings['INCLUDE_ANY'] = true;
+                        if ($serendipity['smarty']->security_settings) {
+                            $inclusion = $serendipity['smarty']->security_settings['INCLUDE_ANY'];
+                            $serendipity['smarty']->security_settings['INCLUDE_ANY'] = true;
+                        }
                         $profile = $this->getConfigVars($serendipity['GET']['viewAuthor']);
                         $local_properties =& $this->getLocalProperties();
                         foreach($local_properties as $property => $info) {
-                            $profile[$property] = $GLOBALS['uInfo'][0][$property];
+                            if (isset($GLOBALS['uInfo'])) {
+                                $profile[$property] = $GLOBALS['uInfo'][0][$property];
+                            }
+                            else {
+                                $profile[$property] = null;
+                            }
                         }
 
                         $properties = array();
@@ -559,7 +567,9 @@ function event_hook($event, &$bag, &$eventData, $addData = null) {
                         $serendipity['smarty']->assign('userProfileTitle', PLUGIN_EVENT_USERPROFILES_SHOW);
 
                         $content = $serendipity['smarty']->fetch('file:'. $tfile);
-                        $serendipity['smarty']->security_settings['INCLUDE_ANY'] = $inclusion;
+                        if ($serendipity['smarty']->security_settings) {
+                            $serendipity['smarty']->security_settings['INCLUDE_ANY'] = $inclusion;
+                        }
 
                         echo $content;
                     }
@@ -619,6 +629,9 @@ function event_hook($event, &$bag, &$eventData, $addData = null) {
                         return true;
                     }
 
+                    if (!isset($eventData['authorid'])) {
+                        return true;
+                    }
                     if (empty($eventData['author'])) {
                         $tmp = serendipity_fetchAuthor($eventData['authorid']);
                         $author = $tmp[0]['realname'];
diff --git a/serendipity_event_userprofiles/serendipity_plugin_userprofiles.php b/serendipity_event_userprofiles/serendipity_plugin_userprofiles.php
index b983f8a0e..649f3fb57 100644
--- a/serendipity_event_userprofiles/serendipity_plugin_userprofiles.php
+++ b/serendipity_event_userprofiles/serendipity_plugin_userprofiles.php
@@ -1,6 +1,6 @@
 <?php # 
 
-# (c) by Falk Döring
+# (c) by Falk D�ring
 
 
 if (IN_serendipity !== true) {
@@ -10,11 +10,12 @@
 @serendipity_plugin_api::load_language(dirname(__FILE__));
 
 class serendipity_plugin_userprofiles extends serendipity_plugin {
+    protected $dependencies = array();
 
     function introspect(&$propbag) {
         $propbag->add('name',        PLUGIN_USERPROFILES_NAME);
         $propbag->add('description', PLUGIN_USERPROFILES_NAME_DESC);
-        $propbag->add('author',      "Falk Döring");
+        $propbag->add('author',      "Falk D�ring");
         $propbag->add('stackable',   false);
         $propbag->add('version',     '1.2.2');
         $propbag->add('configuration', array('title', 'show_groups', 'show_users'));
diff --git a/serendipity_event_userprofiles/serendipity_plugin_userprofiles_birthdays.php b/serendipity_event_userprofiles/serendipity_plugin_userprofiles_birthdays.php
index 4ef348843..f894547ff 100644
--- a/serendipity_event_userprofiles/serendipity_plugin_userprofiles_birthdays.php
+++ b/serendipity_event_userprofiles/serendipity_plugin_userprofiles_birthdays.php
@@ -8,6 +8,7 @@
 @serendipity_plugin_api::load_language(dirname(__FILE__));
 
 class serendipity_plugin_userprofiles_birthdays extends serendipity_plugin {
+    protected $dependencies = array();
 
     function introspect(&$propbag) {
         $propbag->add('name',        PLUGIN_USERPROFILES_BIRTHDAYSNAME);