diff --git a/admin/admin_submit_ticket.php b/admin/admin_submit_ticket.php
index 56cce5d4..53386536 100644
--- a/admin/admin_submit_ticket.php
+++ b/admin/admin_submit_ticket.php
@@ -139,8 +139,7 @@ foreach ($hesk_settings['custom_fields'] as $k=>$v) {
         } elseif ($v['type'] == 'date') {
             $tmpvar[$k] = hesk_POST($k);
             $_SESSION["as_$k"] = '';
-
-            if (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $tmpvar[$k])) {
+            if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $tmpvar[$k])) {
                 $date = strtotime($tmpvar[$k] . ' t00:00:00');
                 $dmin = strlen($v['value']['dmin']) ? strtotime($v['value']['dmin'] . ' t00:00:00') : false;
                 $dmax = strlen($v['value']['dmax']) ? strtotime($v['value']['dmax'] . ' t00:00:00') : false;
diff --git a/admin/custom_fields.php b/admin/custom_fields.php
index b8a7ef8d..bdfc69ab 100755
--- a/admin/custom_fields.php
+++ b/admin/custom_fields.php
@@ -287,7 +287,7 @@ require_once(HESK_PATH . 'inc/show_admin_nav.inc.php');
 															$dmin_type = $matches[3];
 														}
 														// Minimum date is in "MM/DD/YYYY" format
-														elseif (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $dmin))
+														elseif (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $dmin))
 														{
 															$dmin_rf = 1;
 														}
@@ -359,7 +359,7 @@ require_once(HESK_PATH . 'inc/show_admin_nav.inc.php');
 															$dmax_type = $matches[3];
 														}
 														// Minimum date is in "MM/DD/YYYY" format
-														elseif (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $dmax))
+														elseif (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $dmax))
 														{
 															$dmax_rf = 1;
 														}
@@ -1110,7 +1110,7 @@ function cf_validate()
             {
             	$dmin = hesk_POST('dmin');
 
-            	if (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $dmin))
+            	if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $dmin))
                 {
                 	$cf['dmin'] = $dmin;
                 }
@@ -1135,7 +1135,7 @@ function cf_validate()
             {
             	$dmax = hesk_POST('dmax');
 
-            	if (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $dmax))
+            	if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $dmax))
                 {
                 	$cf['dmax'] = $dmax;
                 }
diff --git a/admin/edit_post.php b/admin/edit_post.php
index 1b15e20e..354f2a34 100644
--- a/admin/edit_post.php
+++ b/admin/edit_post.php
@@ -166,7 +166,7 @@ if (isset($_POST['save'])) {
                     $tmpvar[$k] = hesk_POST($k);
                     $_SESSION["as_$k"] = '';
 
-                    if (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $tmpvar[$k])) {
+                    if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $tmpvar[$k])) {
                         $date = strtotime($tmpvar[$k] . ' t00:00:00');
                         $dmin = strlen($v['value']['dmin']) ? strtotime($v['value']['dmin'] . ' t00:00:00') : false;
                         $dmax = strlen($v['value']['dmax']) ? strtotime($v['value']['dmax'] . ' t00:00:00') : false;
diff --git a/submit_ticket.php b/submit_ticket.php
index 81cea406..0a015ce5 100644
--- a/submit_ticket.php
+++ b/submit_ticket.php
@@ -284,7 +284,7 @@ foreach ($hesk_settings['custom_fields'] as $k=>$v) {
             $tmpvar[$k] = hesk_POST($k);
             $_SESSION["c_$k"] = '';
 
-            if (preg_match("/^[0-9]{2}\/[0-9]{2}\/[0-9]{4}$/", $tmpvar[$k])) {
+            if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/", $tmpvar[$k])) {
                 $date = strtotime($tmpvar[$k] . ' t00:00:00');
                 $dmin = strlen($v['value']['dmin']) ? strtotime($v['value']['dmin'] . ' t00:00:00') : false;
                 $dmax = strlen($v['value']['dmax']) ? strtotime($v['value']['dmax'] . ' t00:00:00') : false;