diff --git a/dibi/libs/DibiDateTime.php b/dibi/libs/DibiDateTime.php
index df75552..6f6e923 100644
--- a/dibi/libs/DibiDateTime.php
+++ b/dibi/libs/DibiDateTime.php
@@ -48,14 +48,23 @@ class DibiDateTime extends DateTime
 
 	public function __sleep()
 	{
-		$this->fix = array($this->format('Y-m-d H:i:s'), $this->getTimezone()->getName());
+		$zone = $this->getTimezone()->getName();
+		if ($zone[0] === '+') {
+			$this->fix = array($this->format('Y-m-d H:i:sP'));
+		} else {
+			$this->fix = array($this->format('Y-m-d H:i:s'), $zone);
+		}
 		return array('fix');
 	}
 
 
 	public function __wakeup()
 	{
-		$this->__construct($this->fix[0], new DateTimeZone($this->fix[1]));
+		if (isset($this->fix[1])) {
+			$this->__construct($this->fix[0], new DateTimeZone($this->fix[1]));
+		} else {
+			$this->__construct($this->fix[0]);
+		}
 		unset($this->fix);
 	}