diff --git a/README.md b/README.md
index 16ea29f..d4daa2c 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,10 @@
 # Moodle - Local Reminders
 ---
-![Version](https://img.shields.io/badge/version-v2.4-blue)
+![Version](https://img.shields.io/badge/version-v2.5-blue)
 ![Moodle Version](https://img.shields.io/badge/moodle-%3E%3D%203.5-orange)
+![Maturiy](https://img.shields.io/badge/maturity-STABLE-brightgreen)
 ![License](https://img.shields.io/badge/license-GPL%20v3-green)
+![Maintenance](https://img.shields.io/maintenance/yes/2022)
 [![Build Status](https://github.com/isuru89/moodle-local_reminders/actions/workflows/moodle-ci.yml/badge.svg?branch=release_2.0)](https://github.com/isuru89/moodle-local_reminders/actions/workflows/moodle-ci.yml)
 
 This plugin will send email reminders for [Moodle](https://moodle.org/) calendar events.
@@ -25,11 +27,12 @@ In addition to that, there are lot of new features introduced in v2 of the plugi
  * Send reminders to users who unable to complete an expired activity.
  * Send email reminders when a calendar event is created, updated or removed.
  * Ability to enable/disable and scheduling reminders per activity basis.
+ * Ability to customize email header and footer contents
  * Ability to exclude specific set of activity types from sending reminders.
  * No reminders after a user has completed activity.
  * Added event location / timezone information to the reminder email.
- * New category event type support
- * Improved email style
+ * New category event type support.
+ * Honours activity overriddes and extensions.
 
 And many bug fixes too.
 
@@ -96,6 +99,11 @@ In addition to above, user can control reminders for calendar event changes per
 
 ## Changelog
 
+### v2.5
+  * Ability to customize reminder email header and footer #137 #135
+  * Bug fix on user and group overrides and extensions #134
+  * Minor bug fixes #136
+
 ### v2.4
   * Ability to explicitly turn on reminders instead of enabling by default for all (#129, #130)
 
diff --git a/classes/calendar_observer.php b/classes/calendar_observer.php
index bb37985..4e81f4a 100644
--- a/classes/calendar_observer.php
+++ b/classes/calendar_observer.php
@@ -69,4 +69,4 @@ public static function calendar_event_added($event) {
         when_calendar_event_updated($event, REMINDERS_CALENDAR_EVENT_ADDED);
     }
 
-}
\ No newline at end of file
+}
diff --git a/classes/privacy/provider.php b/classes/privacy/provider.php
index 9e92997..1ef4bd8 100644
--- a/classes/privacy/provider.php
+++ b/classes/privacy/provider.php
@@ -43,4 +43,4 @@ class provider implements
     public static function get_reason() : string {
         return 'privacy:metadata';
     }
-}
\ No newline at end of file
+}
diff --git a/contents/category_reminder.class.php b/contents/category_reminder.class.php
index dead684..4a70d98 100644
--- a/contents/category_reminder.class.php
+++ b/contents/category_reminder.class.php
@@ -67,6 +67,7 @@ public function __construct($event, $coursecategory, $aheaddays = 1) {
     public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/contents/course_reminder.class.php b/contents/course_reminder.class.php
index 69adcb2..8179974 100644
--- a/contents/course_reminder.class.php
+++ b/contents/course_reminder.class.php
@@ -67,6 +67,7 @@ public function __construct($event, $course, $aheaddays = 1) {
     public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/contents/due_reminder.class.php b/contents/due_reminder.class.php
index a854504..302cf35 100644
--- a/contents/due_reminder.class.php
+++ b/contents/due_reminder.class.php
@@ -140,6 +140,7 @@ public function filter_authorized_users($users, $type=null) {
     public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/contents/group_reminder.class.php b/contents/group_reminder.class.php
index 60cc877..31653f0 100644
--- a/contents/group_reminder.class.php
+++ b/contents/group_reminder.class.php
@@ -135,6 +135,7 @@ public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
 
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/contents/site_reminder.class.php b/contents/site_reminder.class.php
index 15db37a..95e957f 100644
--- a/contents/site_reminder.class.php
+++ b/contents/site_reminder.class.php
@@ -48,6 +48,7 @@ class site_reminder extends local_reminder {
     public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/contents/user_reminder.class.php b/contents/user_reminder.class.php
index 282958f..a723790 100644
--- a/contents/user_reminder.class.php
+++ b/contents/user_reminder.class.php
@@ -78,6 +78,7 @@ public function cleanup() {
     public function get_message_html($user=null, $changetype=null, $ctxinfo=null) {
         $htmlmail = $this->get_html_header();
         $htmlmail .= html_writer::start_tag('body', array('id' => 'email'));
+        $htmlmail .= $this->get_reminder_header();
         $htmlmail .= html_writer::start_tag('div');
         $htmlmail .= html_writer::start_tag('table',
                 array('cellspacing' => 0, 'cellpadding' => 8, 'style' => $this->tbodycssstyle));
diff --git a/coursesettings_form.php b/coursesettings_form.php
index ba9c957..ee8785b 100644
--- a/coursesettings_form.php
+++ b/coursesettings_form.php
@@ -211,4 +211,4 @@ private function generate_event_link($event) {
 
         return $calurl->out(false);
     }
-}
\ No newline at end of file
+}
diff --git a/db/events.php b/db/events.php
index b2e1ea7..090f2da 100644
--- a/db/events.php
+++ b/db/events.php
@@ -37,4 +37,4 @@
         'eventname' => '\core\event\calendar_event_deleted',
         'callback' => '\local_reminders\calendar_observer::calendar_event_removed'
     )
-);
\ No newline at end of file
+);
diff --git a/db/upgrade.php b/db/upgrade.php
index 28e23b8..85a087e 100644
--- a/db/upgrade.php
+++ b/db/upgrade.php
@@ -140,4 +140,4 @@ function create_local_reminders_post_activity_table($dbman) {
     if (!$dbman->table_exists($table)) {
         $dbman->create_table($table);
     }
-}
\ No newline at end of file
+}
diff --git a/lang/en/local_reminders.php b/lang/en/local_reminders.php
index 8470b83..40f6c2a 100644
--- a/lang/en/local_reminders.php
+++ b/lang/en/local_reminders.php
@@ -57,6 +57,13 @@
 $string['days3'] = '3 Days';
 $string['days1'] = '1 Day';
 $string['dueheading'] = 'Activity Event Reminders';
+$string['emailconfigsheading'] = 'Reminder Email Customization';
+$string['emailfootercustomname'] = 'Custom Email Footer';
+$string['emailfootercustomnamedesc'] = 'Specify the footer content to be embedded in every reminder email message. If this content is empty and default footer is disabled, then footer will remove completely from reminders.';
+$string['emailfooterdefaultname'] = 'Use Default Email Footer';
+$string['emailfooterdefaultnamedesc'] = 'If checked, then default reminder email footer will contain a link to the Moodle calendar. Otherwise, the content provided in customized footer will be used.';
+$string['emailheadercustomname'] = 'Custom Email Header';
+$string['emailheadercustomnamedesc'] = 'Specify the header content to be embedded in every reminder email message. This can be use to brand these email messages to your site.';
 $string['enabled'] = 'Enabled';
 $string['enabledoverdue'] = 'Overdue Enabled';
 $string['enableddescription'] = 'Enable/disable reminder plugin';
diff --git a/lib.php b/lib.php
index 0e4cc4b..67828c9 100644
--- a/lib.php
+++ b/lib.php
@@ -76,6 +76,10 @@
 define('REMINDERS_CLEAN_TABLE', 'local_reminders');
 define('REMINDERS_ENABLED_KEY', 'enabled');
 
+define('REMINDERS_SUPPORTED_OVERRIDES', array('assign', 'quiz'));
+define('REMINDERS_SUPPORTED_OVERRIDES_REF_IDS', array('assign' => 'assignid', 'quiz' => 'quiz'));
+
+
 /**
  * ======== FUNCTIONS =========================================
  */
diff --git a/locallib.php b/locallib.php
index 87218f6..ecddfab 100644
--- a/locallib.php
+++ b/locallib.php
@@ -287,7 +287,7 @@ function handle_course_activity_event($event, $course, $cm, $options) {
         $showtrace && mtrace("  [Local Reminder] Event #".$event->id." is a user overridden ".$event->modulename." event.");
         $user = $DB->get_record('user', array('id' => $event->userid));
         $sendusers[] = $user;
-    } else if ($event->courseid <= 0 && $event->groupid > 0) {
+    } else if ($event->groupid > 0) {
         // A group overridden activity.
         $showtrace && mtrace("  [Local Reminder] Event #".$event->id." is a group overridden ".$event->modulename." event.");
         $group = $DB->get_record('groups', array('id' => $event->groupid));
@@ -296,6 +296,7 @@ function handle_course_activity_event($event, $course, $cm, $options) {
         // Here 'ra.id field added to avoid printing debug message,
         // from get_role_users (has odd behaivior when called with an array for $roleid param'.
         $sendusers = get_active_role_users($options->activityroleids, $context);
+        $sendusers = filter_user_group_overrides($event, $sendusers, $showtrace);
 
         // Filter user list,
         // see: https://docs.moodle.org/dev/Availability_API.
@@ -689,12 +690,61 @@ function get_correct_timeformat_user($user) {
  * @return array of user records
  */
 function get_active_role_users($activityroleids, $context) {
-    return get_role_users($activityroleids, $context, true, 'ra.id, u.*',
+    return get_role_users($activityroleids, $context, true, 'ra.id as ra_id, u.*',
                     null, false, '', '', '',
                     'ue.status = :userenrolstatus',
                     array('userenrolstatus' => ENROL_USER_ACTIVE));
 }
 
+/**
+ * Filter and return eligible set of users after excluding users who belongs
+ * in overridden extensions.
+ *
+ * @param object $event source event object.
+ * @param array $sendusers all users for this activity instance.
+ * @param bool $showtrace to print logs or not.
+ * @return array filtered out users.
+ */
+function filter_user_group_overrides($event, $sendusers, $showtrace) {
+    global $DB;
+
+    if (!in_array($event->modulename, REMINDERS_SUPPORTED_OVERRIDES)) {
+        return $sendusers;
+    }
+
+    $showtrace && mtrace("  [Local Reminder] Event supports overrides for key ");
+    $idcolumn = REMINDERS_SUPPORTED_OVERRIDES_REF_IDS[$event->modulename];
+    $overridesrecords = $DB->get_records($event->modulename.'_overrides', array($idcolumn => $event->instance));
+    if (empty($overridesrecords)) {
+        $showtrace && mtrace("  [Local Reminder] No overrides for activity ".$event->instance."!");
+        return $sendusers;
+    }
+
+    $extendedusers = [];
+    foreach ($overridesrecords as $record) {
+        if ($record->userid > 0) {
+            $showtrace && mtrace("     Overrides for user id: ".$record->userid);
+            $extendedusers[] = $record->userid;
+        } else if ($record->groupid > 0) {
+            $showtrace && mtrace("     Overrides for group id: ".$record->groupid);
+            $groupmemberroles = groups_get_members_by_role($record->groupid, $event->courseid, 'u.id');
+            if (!empty($groupmemberroles)) {
+                foreach ($groupmemberroles as $roleid => $roledata) {
+                    foreach ($roledata->users as $member) {
+                        $extendedusers[] = $member->id;
+                    }
+                }
+            }
+        }
+    }
+
+    $finalarray = array_filter($sendusers, function($it) use ($extendedusers) {
+        return !in_array($it->id, $extendedusers);
+    });
+    return $finalarray;
+}
+
+
 /**
  * Returns all users belong to the given group.
  *
diff --git a/reminder.class.php b/reminder.class.php
index f4eb9d4..c60cdf6 100644
--- a/reminder.class.php
+++ b/reminder.class.php
@@ -90,6 +90,17 @@ abstract class local_reminder {
      * @var string
      */
     protected $footerstyle = 'background-color:#f6f6f6;'.
+        'color:#888;'.
+        'border-top:1px solid #ccc;'.
+        'font-family:Arial,Sans-serif;'.
+        'font-size:11px;'.
+        'padding: 0px;';
+    /**
+     * CSS styles for default footer content.
+     *
+     * @var string
+     */
+    protected $footerdefstyle = 'background-color:#f6f6f6;'.
         'color:#888;'.
         'border-top:1px solid #ccc;'.
         'font-family:Arial,Sans-serif;'.
@@ -221,6 +232,22 @@ protected function get_html_header() {
         return html_writer::tag('head', '');
     }
 
+    /**
+     * Returns the header content of the reminder email. This part can be use to brand
+     * all of these email messages, such as with logo etc.
+     *
+     */
+    protected function get_reminder_header() {
+        global $CFG;
+
+        if (isset($CFG->local_reminders_emailheadercustom) && trim($CFG->local_reminders_emailheadercustom) !== '') {
+            $htmltext = html_writer::start_tag('div');
+            $htmltext .= text_to_html($CFG->local_reminders_emailheadercustom, false, false, true);
+            return $htmltext.html_writer::end_tag('div');
+        }
+        return '';
+    }
+
     /**
      * Returns time zone info for a user in plain text format.
      *
@@ -251,14 +278,24 @@ protected function pluralize($number, $text) {
     protected function get_html_footer() {
         global $CFG;
 
+        $footer = html_writer::start_tag('tr');
         $moodlecalendarname = get_string('moodlecalendarname', 'local_reminders');
         $calendarlink = html_writer::link($CFG->wwwroot.'/calendar/index.php', $moodlecalendarname, array('target' => '_blank'));
-        $footer = html_writer::start_tag('tr');
-        $footer .= html_writer::start_tag('td', array('style' => $this->footerstyle, 'colspan' => 2));
-        $footer .= get_string('reminderfrom', 'local_reminders').' ';
-        $footer .= $calendarlink;
-        $footer .= html_writer::end_tag('td').html_writer::end_tag('tr');
 
+        if (isset($CFG->local_reminders_emailfooterdefaultenabled) && $CFG->local_reminders_emailfooterdefaultenabled) {
+            $footer .= html_writer::start_tag('td', array('style' => $this->footerdefstyle, 'colspan' => 2));
+            $footer .= get_string('reminderfrom', 'local_reminders').' ';
+            $footer .= $calendarlink;
+
+        } else if (isset($CFG->local_reminders_emailfootercustom) && trim($CFG->local_reminders_emailfootercustom) !== '') {
+            $footer .= html_writer::start_tag('td', array('style' => $this->footerstyle, 'colspan' => 2));
+            $footer .= text_to_html($CFG->local_reminders_emailfootercustom, false, false, true);
+
+        } else {
+            return '';
+        }
+
+        $footer .= html_writer::end_tag('td').html_writer::end_tag('tr');
         return $footer;
     }
 
diff --git a/settings.php b/settings.php
index 8ead85f..fa85269 100644
--- a/settings.php
+++ b/settings.php
@@ -92,6 +92,25 @@
             array(),
             $excludedoptions));
 
+    // REMINDER EMAIL CONFIGURATIONS.
+    $settings->add(new admin_setting_heading('local_reminders_heading_emailcutomizations',
+            get_string('emailconfigsheading', 'local_reminders'), ''));
+
+    $settings->add(new admin_setting_confightmleditor('local_reminders_emailheadercustom',
+        get_string('emailheadercustomname', 'local_reminders'),
+        get_string('emailheadercustomnamedesc', 'local_reminders'), ''));
+
+    $settings->add(new admin_setting_configcheckbox('local_reminders_emailfooterdefaultenabled',
+        get_string('emailfooterdefaultname', 'local_reminders'),
+        get_string('emailfooterdefaultnamedesc', 'local_reminders'), 1));
+
+    $settings->add(new admin_setting_confightmleditor('local_reminders_emailfootercustom',
+        get_string('emailfootercustomname', 'local_reminders'),
+        get_string('emailfootercustomnamedesc', 'local_reminders'), ''));
+
+    // END OF EMAIL CONFIGURATIONS.
+
+
     $daysarray = array('days7' => ' '.get_string('days7', 'local_reminders'),
                        'days3' => ' '.get_string('days3', 'local_reminders'),
                        'days1' => ' '.get_string('days1', 'local_reminders'));
@@ -305,4 +324,4 @@
     $settings->add(new admin_setting_configcheckbox('local_reminders_enable_categoryforcalevents',
             get_string('enabledforcalevents', 'local_reminders'),
             get_string('enabledforcaleventsdescription', 'local_reminders'), 0));
-}
\ No newline at end of file
+}
diff --git a/version.php b/version.php
index 30b0651..0f4802d 100644
--- a/version.php
+++ b/version.php
@@ -25,8 +25,8 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version   = 2021062000;
+$plugin->version   = 2021092600;
 $plugin->requires  = 2018051700;        // Require moodle 3.5 or higher.
-$plugin->release   = '2.4';
-$plugin->maturity  = MATURITY_RC;
+$plugin->release   = '2.5';
+$plugin->maturity  = MATURITY_STABLE;
 $plugin->component = 'local_reminders';