diff --git a/README.md b/README.md
index d73497dd..4ef9b586 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 ![OpenSupports](http://www.opensupports.com/logo.png)
 
-[![Build Status](https://travis-ci.org/opensupports/opensupports.svg?branch=master)](https://travis-ci.org/opensupports/opensupports) v4.2.0
+[![Build Status](https://travis-ci.org/opensupports/opensupports.svg?branch=master)](https://travis-ci.org/opensupports/opensupports) v4.3.0
 
 OpenSupports is an open source ticket system built primarily with PHP and ReactJS.
 Please, visit our website for more information: [http://www.opensupports.com/](http://www.opensupports.com/)
diff --git a/client/src/app/main/main-layout-footer.js b/client/src/app/main/main-layout-footer.js
index a6b4560b..27c1640d 100644
--- a/client/src/app/main/main-layout-footer.js
+++ b/client/src/app/main/main-layout-footer.js
@@ -7,9 +7,10 @@ class MainLayoutFooter extends React.Component {
     render() {
         return (
             <div className={this.getClass()}>
-                {(this.props.adminPanelOpened) ? this.renderExtraLinks() : null}
+                {this.props.adminPanelOpened ? this.renderExtraLinks() : null}
                 <div className="main-layout-footer__powered">
                     Powered by <a className="main-layout-footer__os-link" href="http://www.opensupports.com/" target="_blank">OpenSupports</a>
+                    <span> {this.props.adminPanelOpened ? `v${opensupports_version}` : null}</span>
                 </div>
             </div>
         );
diff --git a/client/src/config.js b/client/src/config.js
index 1828bbe4..e2013ed3 100644
--- a/client/src/config.js
+++ b/client/src/config.js
@@ -1,3 +1,4 @@
+opensupports_version = '4.3.0';
 root = 'http://localhost:3000';
 apiRoot = 'http://localhost:3000/api';
 globalIndexPath = '';
diff --git a/client/src/index.php b/client/src/index.php
index 76b5baeb..152529e6 100755
--- a/client/src/index.php
+++ b/client/src/index.php
@@ -19,6 +19,7 @@
         <div id="app"></div>
 
         <script>
+            opensupports_version = '4.3.0';
             root = "<?=$url ?>";
             apiRoot = '<?=$url ?>/api';
             globalIndexPath = "<?=$path ?>";
diff --git a/server/controllers/staff/un-assign-ticket.php b/server/controllers/staff/un-assign-ticket.php
index 537e6cff..a162d4d4 100755
--- a/server/controllers/staff/un-assign-ticket.php
+++ b/server/controllers/staff/un-assign-ticket.php
@@ -45,7 +45,7 @@ class UnAssignStaffController extends Controller {
         $ticket = Ticket::getByTicketNumber($ticketNumber);
         $owner = $ticket->owner;
 
-        if($ticket->isOwner($user) || $user->level > 2) {
+        if($owner && ($ticket->isOwner($user) || $user->level > 2)) {
             if(!$ticket->isAuthor($owner)) {
                 $owner->sharedTicketList->remove($ticket);
                 $owner->store();
diff --git a/server/controllers/ticket/comment.php b/server/controllers/ticket/comment.php
index 5b250812..7be2b248 100755
--- a/server/controllers/ticket/comment.php
+++ b/server/controllers/ticket/comment.php
@@ -141,7 +141,7 @@ class CommentController extends Controller {
 
         $email = $recipient['email'];
         $name = $recipient['name'];
-        $isStaff = $recipient['staff'];
+        $isStaff = array_key_exists('staff', $recipient) && $recipient['staff'];
 
         $url = Setting::getSetting('url')->getValue();
 
diff --git a/server/models/Ticket.php b/server/models/Ticket.php
index 702afeec..282bd54e 100755
--- a/server/models/Ticket.php
+++ b/server/models/Ticket.php
@@ -141,6 +141,8 @@ class Ticket extends DataStore {
             ];
         } else {
             return [
+              'id' => NULL,
+              'staff' => false,
               'name' => $this->authorName,
               'email' => $this->authorEmail
             ];
@@ -188,7 +190,7 @@ class Ticket extends DataStore {
             if(!Controller::isStaffLogged() && $ticketEvent->private) {
                 continue;
             }
-    
+
             $events[] = $event;
         }
 
@@ -202,10 +204,11 @@ class Ticket extends DataStore {
     public function isAuthor($user) {
         $ticketAuthor = $this->authorToArray();
         if(is_string($user)) return $user == $ticketAuthor['email'];
+        if(!($user instanceof DataStore) || $user->isNull()) return false;
         return $user->id == $ticketAuthor['id'] && ($user instanceof Staff) == $ticketAuthor['staff'];
     }
 
     public function isOwner($user) {
-        return $this->owner && $user->id == $this->owner->id && ($user instanceof Staff);
+        return !$user->isNull() && $this->owner && $user->id == $this->owner->id && ($user instanceof Staff);
     }
 }
diff --git a/tests/system/disable-user-system.rb b/tests/system/disable-user-system.rb
index 81884ea8..e96adb56 100644
--- a/tests/system/disable-user-system.rb
+++ b/tests/system/disable-user-system.rb
@@ -65,6 +65,40 @@ describe'system/disable-user-system' do
             (result['status']).should.equal('success')
         end
 
+        it 'should be able to assign and respond tickets' do
+            Scripts.login($staff[:email], $staff[:password], true);
+            ticket = $database.getLastRow('ticket');
+            result = request('/staff/assign-ticket', {
+                ticketNumber: ticket['ticket_number'],
+                csrf_userid: $csrf_userid,
+                csrf_token: $csrf_token,
+            })
+            (result['status']).should.equal('success')
+
+            result = request('/ticket/comment', {
+                ticketNumber: ticket['ticket_number'],
+                content: 'This is a staff response for a ticket without an user',
+                csrf_userid: $csrf_userid,
+                csrf_token: $csrf_token,
+            })
+            (result['status']).should.equal('success')
+        end
+
+        it 'should be be able to create a ticket as an admin' do
+            result = request('/ticket/create', {
+                title: 'created by staff with user system disabled',
+                content: 'an staff created this ticket while user system disabled',
+                departmentId: 1,
+                language: 'en',
+                csrf_userid: $csrf_userid,
+                csrf_token: $csrf_token
+            })
+            (result['status']).should.equal('success')
+            ticket = $database.getRow('ticket', result['data']['ticketNumber'], 'ticket_number')
+            (ticket['author_id']).should.equal(nil)
+            (ticket['author_staff_id']).should.equal('1')
+        end
+
         it 'should not disable the user system if it is already disabled 'do
             request('/user/logout')
             Scripts.login($staff[:email], $staff[:password], true)
diff --git a/version_upgrades/4.3.0/4.3.0.php b/version_upgrades/4.3.0/4.3.0.php
new file mode 100644
index 00000000..d1c92246
--- /dev/null
+++ b/version_upgrades/4.3.0/4.3.0.php
@@ -0,0 +1,67 @@
+<?php
+require_once '../mysql_connect.php';
+
+$filePath = '../../api/files';
+
+print 'Begin update v4.3.0...' . PHP_EOL;
+
+// Change profile pics
+print '[1/3] Updating profile pics..' . PHP_EOL;
+$queryResult = $mysql->query("SELECT id,profile_pic FROM staff") or die(PHP_EOL . 'Error: profile_pic can\'t be found on `staff` table'. PHP_EOL);
+while($staff = $queryResult->fetch_array(MYSQLI_ASSOC)) {
+    global $filePath;
+    $id = $staff['id'];
+    $profilePicFileName = $staff['profile_pic'];
+    $updatedProfilePicFileName = "p_$profilePicFileName";
+
+    if(!$profilePicFileName || $profilePicFileName[0] == 'p') continue;
+
+    rename("$filePath/$profilePicFileName", "$filePath/$updatedProfilePicFileName")
+    or die("Error: could not change file name from $profilePicFileName to $updatedProfilePicFileName");
+
+    $mysql->query("UPDATE staff SET profile_pic='$updatedProfilePicFileName' WHERE id='$id'")
+    or die (PHP_EOL . "Error: could not update profile_pic for staff id:$id" . PHP_EOL);
+}
+
+// Change ticket attachments
+print '[2/3] Updating ticket attachments...' . PHP_EOL;
+function updateTicketFile($ticketNumber, $fileName) {
+    global $filePath;
+    $updatedFileName = "t$ticketNumber" . "_$fileName";
+
+    rename("$filePath/$fileName", "$filePath/$updatedFileName")
+    or die(PHP_EOL . "Error: could not change file name from $fileName to $updatedFileName" . PHP_EOL);
+
+    return $updatedFileName;
+}
+
+$queryResult = $mysql->query("SELECT id,ticket_number,file FROM ticket");
+while($queryResult && $ticket = $queryResult->fetch_array(MYSQLI_ASSOC)) {
+    $id = $ticket['id'];
+
+    if(!$ticket['file'] || $ticket['file'][0] == 't') continue;
+
+    $updatedFileName = updateTicketFile($ticket['ticket_number'], $ticket['file']);
+
+    $mysql->query("UPDATE ticket SET file='$updatedFileName' WHERE id='$id'")
+    or die (PHP_EOL . "Error: could not update file for ticket id:$id" . PHP_EOL);
+}
+
+// Change ticket attachments
+print '[3/3] Updating ticketevent attachments...' . PHP_EOL;
+$queryResult = $mysql->query("SELECT id,ticket_id,file FROM ticketevent");
+while($queryResult && $ticketEvent = $queryResult->fetch_array(MYSQLI_ASSOC)) {
+    $id = $ticketEvent['id'];
+    $ticketId = $ticketEvent['ticket_id'];
+    $ticketQuery = $mysql->query("SELECT ticket_number FROM ticket WHERE id='$ticketId'") or die(PHP_EOL . "Error: could not find ticket id:$id" . PHP_EOL);
+    $ticketNumber = $ticketQuery->fetch_array()[0];
+
+    if(!$ticketEvent['file'] || $ticketEvent['file'][0] == 't') continue;
+
+    $updatedFileName = updateTicketFile($ticketNumber, $ticketEvent['file']);
+
+    $mysql->query("UPDATE ticketevent SET file='$updatedFileName' WHERE id='$id'")
+    or die (PHP_EOL . "Error: could not update file for ticketevent id:$id" . PHP_EOL);
+}
+
+print 'Update Completed!' . PHP_EOL;