diff --git a/htdocs/core/lib/date.lib.php b/htdocs/core/lib/date.lib.php
index 71912714b90..c45c5a88e29 100644
--- a/htdocs/core/lib/date.lib.php
+++ b/htdocs/core/lib/date.lib.php
@@ -115,26 +115,28 @@ function getServerTimeZoneInt($refgmtdate='now')
  */
 function dol_time_plus_duree($time, $duration_value, $duration_unit)
 {
+	global $conf;
+
 	if ($duration_value == 0)  return $time;
 	if ($duration_unit == 'h') return $time + (3600*$duration_value);
 	if ($duration_unit == 'w') return $time + (3600*24*7*$duration_value);
-	
+
 	$deltastring='P';
-	
+
 	if ($duration_value > 0){ $deltastring.=abs($duration_value); $sub= false; }
 	if ($duration_value < 0){ $deltastring.=abs($duration_value); $sub= true; }
 	if ($duration_unit == 'd') { $deltastring.="D"; }
 	if ($duration_unit == 'm') { $deltastring.="M"; }
 	if ($duration_unit == 'y') { $deltastring.="Y"; }
-	
+
 	$date = new DateTime();
-	$date->setTimezone(new DateTimeZone('UTC'));
+	if (! empty($conf->global->MAIN_DATE_IN_MEMORY_ARE_GMT)) $date->setTimezone(new DateTimeZone('UTC'));
 	$date->setTimestamp($time);
 	$interval = new DateInterval($deltastring);
-	
+
 	if($sub) $date->sub($interval);
 	else $date->add( $interval );
-	
+
 	return $date->getTimestamp();
 }