diff --git a/libraries/legacy/model/admin.php b/libraries/legacy/model/admin.php
index 73d229ac9552c..a5aa338f5c37b 100644
--- a/libraries/legacy/model/admin.php
+++ b/libraries/legacy/model/admin.php
@@ -1156,6 +1156,13 @@ public function save($data)
 				return false;
 			}
 
+			// When the data contains params, then we need to add them to the item for the custom fields
+			// plugins which do add new params fieldsets
+			if (isset($data['params']) && !isset($table->params) && !isset($table->_params))
+			{
+				$table->_params = $data['params'];
+			}
+
 			// Prepare the row for saving
 			$this->prepareTable($table);
 
diff --git a/plugins/fields/calendar/calendar.php b/plugins/fields/calendar/calendar.php
index ff963799ddbe8..f5c1e6d8ecbdc 100644
--- a/plugins/fields/calendar/calendar.php
+++ b/plugins/fields/calendar/calendar.php
@@ -18,4 +18,104 @@
  */
 class PlgFieldsCalendar extends FieldsPlugin
 {
+	/**
+	 * Transforms the field into an XML element and appends it as child on the given parent. This
+	 * is the default implementation of a field. Form fields which do support to be transformed into
+	 * an XML Element mut implemet the JFormDomfieldinterface.
+	 *
+	 * @param   stdClass    $field   The field.
+	 * @param   DOMElement  $parent  The field node parent.
+	 * @param   JForm       $form    The form.
+	 *
+	 * @return  DOMElement
+	 *
+	 * @since   __DEPLOY_VERSION__
+	 */
+	public function onCustomFieldsPrepareDom($field, DOMElement $parent, JForm $form)
+	{
+		$fieldNode = parent::onCustomFieldsPrepareDom($field, $parent, $form);
+
+		if (!$fieldNode)
+		{
+			return $fieldNode;
+		}
+
+		// Set filter to user UTC
+		$fieldNode->setAttribute('filter', 'USER_UTC');
+
+		return $fieldNode;
+	}
+
+	/**
+	 * Convert date/time format between `date()` and `strftime()`.
+	 *
+	 * Timezone conversion is done for Unix. Windows users must exchange %z and %Z.
+	 *
+	 * Unsupported date formats : S, n, t, L, B, G, u, e, I, P, Z, c, r
+	 * Unsupported strftime formats : %U, %W, %C, %g, %r, %R, %T, %X, %c, %D, %F, %x
+	 *
+	 * Example:
+	 * Convert `%A, %B %e, %Y, %l:%M %P` to `l, F j, Y, g:i a`, and vice versa for "Saturday, March 10, 2001, 5:16 pm".
+	 *
+	 * @param   string  $format  The format to parse.
+	 * @param   string  $syntax  The format's syntax. Either 'strftime' for `strtime()` or 'date' for `date()`.
+	 *
+	 * @return  bool|string  Returns a string formatted according $syntax using the given $format or `false`.
+	 *
+	 * @link http://php.net/manual/en/function.strftime.php#96424
+	 * @link https://gist.github.com/mcaskill/02636e5970be1bb22270
+	 *
+	 * @since   __DEPLOY_VERSION__
+	 */
+	public function changeFormat($format, $syntax = 'strftime')
+	{
+		// Syntax from http://php.net/manual/en/function.strftime.php
+		$strfSyntax = array(
+			// Day - no strf eq : S (created one called %O)
+			'%O', '%d', '%a', '%e', '%A', '%u', '%w', '%j',
+			// Week - no date eq : %U, %W
+			'%V',
+			// Month - no strf eq : n, t
+			'%B', '%m', '%b', '%-m',
+			// Year - no strf eq : L; no date eq : %C, %g
+			'%G', '%Y', '%y',
+			// Time - no strf eq : B, G, u; no date eq : %r, %R, %T, %X
+			'%P', '%p', '%l', '%I', '%H', '%M', '%S',
+			// Timezone - no strf eq : e, I, P, Z
+			'%z', '%Z',
+			// Full Date / Time - no strf eq : c, r; no date eq : %c, %D, %F, %x
+			'%s'
+		);
+
+		// Syntax from http://php.net/manual/en/function.date.php
+		$dateSyntax = array(
+			'S', 'd', 'D', 'j', 'l', 'N', 'w', 'z',
+			'W',
+			'F', 'm', 'M', 'n',
+			'o', 'Y', 'y',
+			'a', 'A', 'g', 'h', 'H', 'i', 's',
+			'O', 'T',
+			'U'
+		);
+
+		// Strftime to date
+		$from = $strfSyntax;
+		$to   = $dateSyntax;
+
+		if ($syntax == 'date')
+		{
+			// Date to strftime
+			$from = $dateSyntax;
+			$to   = $strfSyntax;
+		}
+
+		$pattern = array_map(
+			function ($s) {
+				return '/(?<!\\\\|\%)' . $s . '/';
+			},
+			$from
+		);
+
+		return preg_replace($pattern, $to, $format);
+	}
 }
diff --git a/plugins/fields/calendar/tmpl/calendar.php b/plugins/fields/calendar/tmpl/calendar.php
index 99b909417eb7c..627fc51d4b7ef 100644
--- a/plugins/fields/calendar/tmpl/calendar.php
+++ b/plugins/fields/calendar/tmpl/calendar.php
@@ -16,9 +16,15 @@
 	return;
 }
 
-if (is_array($value))
-{
-	$value = implode(', ', $value);
-}
+// Set up the date based on the user and Joomla timezone
+$date = JFactory::getDate($value, 'UTC');
+$date->setTimezone(new DateTimeZone(JFactory::getUser()->getParam('timezone', JFactory::getConfig()->get('offset'))));
+
+// Get the format for PHP date
+$format = $this->changeFormat($fieldParams->get('format', '%Y-%m-%d'), 'strftime');
+
+// Transform the value with the date format of the plugin
+$value = $date->format($format, true);
 
+// Render the date
 echo htmlentities($value);
diff --git a/plugins/system/fields/fields.php b/plugins/system/fields/fields.php
index 3c95f8f1c05e6..822ac524f6656 100644
--- a/plugins/system/fields/fields.php
+++ b/plugins/system/fields/fields.php
@@ -61,15 +61,13 @@ public function onContentBeforeSave($context, $item, $isNew)
 
 		$params = new Registry;
 
-		// Load the item params from the request
-		$data = JFactory::getApplication()->input->post->get('jform', array(), 'array');
-
-		if (key_exists('params', $data))
+		// Load the params from the item when it doesn't have such a field
+		if (isset($item->_params))
 		{
-			$params->loadArray($data['params']);
+			$params->loadArray($item->_params);
 		}
 
-		// Load the params from the item itself
+		// Load the params from the item when it has a params field
 		if (isset($item->params))
 		{
 			$params->loadString($item->params);