diff --git a/admin/admin_ticket.php b/admin/admin_ticket.php
index d492aefb..287249d5 100644
--- a/admin/admin_ticket.php
+++ b/admin/admin_ticket.php
@@ -671,8 +671,10 @@ require_once(HESK_PATH . 'inc/show_admin_nav.inc.php');
                     <div id="readonly-due-date">
                         <span id="due-date">
                         <?php
-                            $due_date = hesk_date($ticket['due_date'], false);
-                            $current_date = hesk_date();
+                            $due_date = 'None';
+                            if ($ticket['due_date'] != null) {
+                                $due_date = hesk_date($ticket['due_date'], false);
+                            }
                             echo substr($due_date, 0, 10);
                         ?></span><!--<span id="overdue">
                         <?php
@@ -685,9 +687,10 @@ require_once(HESK_PATH . 'inc/show_admin_nav.inc.php');
                         <button id="due-date-button" class="btn btn-default btn-sm">Change</button>
                     </div>
                     <div id="editable-due-date" style="display: none">
-                        <input type="text" class="form-control datepicker" name="due-date" value="<?php echo substr($due_date, 0, 10); ?>"><br>
+                        <input type="text" class="form-control datepicker" name="due-date" value="<?php echo $due_date == 'None' ? '' : substr($due_date, 0, 10); ?>"><br>
                         <div class="btn-group">
                             <button id="submit" class="btn btn-primary">Save</button>
+                            <button id="clear" class="btn btn-danger">No Due Date</button>
                             <button id="cancel" class="btn btn-default">Cancel</button>
                         </div>
                     </div>
diff --git a/admin/calendar.php b/admin/calendar.php
index 732d68a2..98b5a1f8 100644
--- a/admin/calendar.php
+++ b/admin/calendar.php
@@ -77,7 +77,7 @@ require_once(HESK_PATH . 'inc/show_admin_nav.inc.php');
                         <div class="checkbox">
                             <input type="checkbox" name="category-toggle" value="<?php echo $category['id']; ?>" checked>
                         </div>
-                        <span class="label background-volitaile category-label" style="<?php echo $category['css_style']; ?>">
+                        <span class="label background-volatile category-label" style="<?php echo $category['css_style']; ?>">
                             <?php echo $category['name']; ?>
                         </span>
                     </li>
diff --git a/install/mods-for-hesk/sql/installSql.php b/install/mods-for-hesk/sql/installSql.php
index 95d3fd81..65db8268 100644
--- a/install/mods-for-hesk/sql/installSql.php
+++ b/install/mods-for-hesk/sql/installSql.php
@@ -728,7 +728,7 @@ function execute260Scripts()
       `name` VARCHAR(255) NOT NULL,
       `location` VARCHAR(255),
       `comments` MEDIUMTEXT,
-      `category` INT) ENGINE = MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci");
+      `category` INT NOT NULL) ENGINE = MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci");
     executeQuery("ALTER TABLE `" . hesk_dbEscape($hesk_settings['db_pfix']) . "tickets` ADD COLUMN `due_date` DATETIME");
     executeQuery("ALTER TABLE `" . hesk_dbEscape($hesk_settings['db_pfix']) . "categories` ADD COLUMN `color` VARCHAR(7)");
     executeQuery("UPDATE `" . hesk_dbEscape($hesk_settings['db_pfix']) . "settings` SET `Value` = '2.6.0' WHERE `Key` = 'modsForHeskVersion'");
diff --git a/internal-api/admin/calendar/index.php b/internal-api/admin/calendar/index.php
index 25db18d6..8e86db77 100644
--- a/internal-api/admin/calendar/index.php
+++ b/internal-api/admin/calendar/index.php
@@ -44,6 +44,7 @@ if ($request_method === 'GET') {
         }
         $event['id'] = hesk_POST('id');
         $event['title'] = hesk_POST('title');
+        $event['location'] = hesk_POST('location');
         $event['start'] = hesk_POST('startTime');
         $event['end'] = hesk_POST('endTime');
         $event['all_day'] = hesk_POST('allDay') === 'true';
diff --git a/internal-api/dao/calendar_dao.php b/internal-api/dao/calendar_dao.php
index 30218987..d944bfda 100644
--- a/internal-api/dao/calendar_dao.php
+++ b/internal-api/dao/calendar_dao.php
@@ -26,7 +26,8 @@ function get_events($start, $end, $hesk_settings) {
         $events[] = $event;
     }
 
-    $sql = "SELECT `trackid`, `subject`, `due_date`, `category`, `categories`.`name` AS `category_name`
+    $sql = "SELECT `trackid`, `subject`, `due_date`, `category`, `categories`.`name` AS `category_name`, `categories`.`color` AS `category_color`,
+      CASE WHEN `due_date` < CURDATE() THEN 1 ELSE 0 END AS `overdue`
     FROM `" . hesk_dbEscape($hesk_settings['db_pfix']) . "tickets` AS `tickets`
     INNER JOIN `" . hesk_dbEscape($hesk_settings['db_pfix']) . "categories` AS `categories`
         ON `categories`.`id` = `tickets`.`category`
@@ -43,7 +44,7 @@ function get_events($start, $end, $hesk_settings) {
         $event['url'] = $hesk_settings['hesk_url'] . '/' . $hesk_settings['admin_dir'] . '/admin_ticket.php?track=' . $event['trackingId'];
         $event['categoryId'] = $row['category'];
         $event['categoryName'] = $row['category_name'];
-        $event['categoryColor'] = 'green';
+        $event['categoryColor'] = $row['overdue'] ? '#dd0000' : $row['category_color'];
         $events[] = $event;
     }
 
diff --git a/internal-api/js/admin-ticket.js b/internal-api/js/admin-ticket.js
index a77ca5be..c8343e2f 100644
--- a/internal-api/js/admin-ticket.js
+++ b/internal-api/js/admin-ticket.js
@@ -17,7 +17,7 @@ $(document).ready(function() {
         var newDueDate = $editableDueDateContainer.find('input[type="text"][name="due-date"]').val();
         $.ajax({
             method: 'POST',
-            url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+            url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
             data: {
                 trackingId: $('input[type="hidden"][name="track"]').val(),
                 action: 'update-ticket',
diff --git a/js/calendar/mods-for-hesk-calendar.js b/js/calendar/mods-for-hesk-calendar.js
index 52e127ce..b6ecc57a 100644
--- a/js/calendar/mods-for-hesk-calendar.js
+++ b/js/calendar/mods-for-hesk-calendar.js
@@ -43,7 +43,7 @@ $(document).ready(function() {
             if (event.type === 'TICKET') {
                 $.ajax({
                     method: 'POST',
-                    url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+                    url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
                     data: {
                         trackingId: event.trackingId,
                         action: 'update-ticket',
@@ -80,7 +80,7 @@ $(document).ready(function() {
                 };
                 $.ajax({
                     method: 'POST',
-                    url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+                    url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
                     data: data,
                     success: function() {
                         $.jGrowl('Event successfully updated', { theme: 'alert-success', closeTemplate: '' });
@@ -167,7 +167,7 @@ $(document).ready(function() {
 
         $.ajax({
             method: 'POST',
-            url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+            url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
             data: data,
             success: function() {
                 removeFromCalendar(data.id);
@@ -204,12 +204,13 @@ $(document).ready(function() {
             categoryId: $('#create-form select[name="category"]').val(),
             action: 'create',
             type: 'CALENDAR',
-            categoryColor: $('#create-form select[name="category"] :selected').attr('data-color')
+            categoryColor: $('#create-form select[name="category"] :selected').attr('data-color'),
+            categoryName: $('#create-form select[name="category"] :selected').text().trim()
         };
 
         $.ajax({
             method: 'POST',
-            url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+            url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
             data: data,
             success: function(id) {
                 addToCalendar(id, data, "Event successfully created");
@@ -246,12 +247,14 @@ $(document).ready(function() {
             allDay: allDay,
             comments: $form.find('textarea[name="comments"]').val(),
             categoryId: $form.find('select[name="category"]').val(),
+            categoryColor: $form.find('select[name="category"] :selected').attr('data-color'),
+            categoryName: $form.find('select[name="category"] :selected').text().trim(),
             action: 'update'
         };
 
         $.ajax({
             method: 'POST',
-            url: getHelpdeskUrl() + '/internal-api/admin/calendar',
+            url: getHelpdeskUrl() + '/internal-api/admin/calendar/',
             data: data,
             success: function() {
                 removeFromCalendar(data.id);
@@ -290,11 +293,12 @@ function buildEvent(id, dbObject) {
             trackingId: dbObject.trackingId,
             start: moment(dbObject.startTime),
             url: dbObject.url,
-            color: endOfDay.isBefore() ? '#dd0000' : 'green',
+            color: dbObject.categoryColor === '' || dbObject.categoryColor === null ? '#fff' : dbObject.categoryColor,
             allDay: true,
             type: dbObject.type,
             categoryId: dbObject.categoryId,
-            className: 'category-' + dbObject.categoryId
+            className: 'category-' + dbObject.categoryId,
+            textColor: calculateTextColor(dbObject.categoryColor)
         };
     }
 
@@ -310,12 +314,16 @@ function buildEvent(id, dbObject) {
         categoryId: dbObject.categoryId,
         categoryName: dbObject.categoryName,
         className: 'category-' + dbObject.categoryId,
-        color: dbObject.categoryColor,
+        color: dbObject.categoryColor === '' || dbObject.categoryColor === null ? '#fff' : dbObject.categoryColor,
         textColor: calculateTextColor(dbObject.categoryColor)
     };
 }
 
 function calculateTextColor(color) {
+    if (color === null || color === '') {
+        return 'black';
+    }
+
     var red = 0;
     var green = 0;
     var blue = 0;
@@ -394,6 +402,7 @@ function displayEditModal(date) {
         createTicketLink += encodeURI(' @ ' + date.location);
     }
     createTicketLink += encodeURI('&message=' + date.comments);
+    createTicketLink += encodeURI('&category=' + date.categoryId);
 
     $form.find('#create-ticket-button').prop('href', createTicketLink);