diff --git a/config/config.sample.php b/config/config.sample.php
index a9ab67374f85827dfd447a31455b235c74011f62..3d1829e17e65d0a00c854256d66e3f2d1db7e7c4 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -716,9 +716,8 @@ $CONFIG = array(
 /**
  * This uses PHP.date formatting; see http://php.net/manual/en/function.date.php
  *
- * Defaults to ``Y-m-d\TH:i:sP`` (ISO8601 but with colon between hours and
- * minutes of the timezone) - see \DateTime::ISO8601
- * (https://secure.php.net/manual/en/class.datetime.php#datetime.constants.iso8601)
+ * Defaults to ISO 8601 ``2005-08-15T15:52:01+00:00`` - see \DateTime::ATOM
+ * (https://secure.php.net/manual/en/class.datetime.php#datetime.constants.atom)
  */
 'logdateformat' => 'F d, Y H:i:s',
 
diff --git a/lib/private/Console/TimestampFormatter.php b/lib/private/Console/TimestampFormatter.php
index d68db95f645b0f856eaef6f757c68baa5d768a66..66dd38e6ac32510fd3abd3cee73f5583480e6fc3 100644
--- a/lib/private/Console/TimestampFormatter.php
+++ b/lib/private/Console/TimestampFormatter.php
@@ -97,11 +97,11 @@ class TimestampFormatter implements OutputFormatterInterface {
 	 */
 	public function format($message) {
 
-		$timeZone = $this->config->getSystemValue('logtimezone', null);
+		$timeZone = $this->config->getSystemValue('logtimezone', 'UTC');
 		$timeZone = $timeZone !== null ? new \DateTimeZone($timeZone) : null;
 
 		$time = new \DateTime('now', $timeZone);
-		$timestampInfo = $time->format($this->config->getSystemValue('logdateformat', \DateTime::ISO8601));
+		$timestampInfo = $time->format($this->config->getSystemValue('logdateformat', \DateTime::ATOM));
 
 		return $timestampInfo . ' ' . $this->formatter->format($message);
 	}
diff --git a/lib/private/Log/File.php b/lib/private/Log/File.php
index d41ab83c804be87eca095a1fbfe1f55cd22cf562..be8b72b3a3fcbb5a59134fb4101bc51737047e1b 100644
--- a/lib/private/Log/File.php
+++ b/lib/private/Log/File.php
@@ -75,7 +75,7 @@ class File {
 		$config = \OC::$server->getSystemConfig();
 
 		// default to ISO8601
-		$format = $config->getValue('logdateformat', \DateTime::ISO8601);
+		$format = $config->getValue('logdateformat', \DateTime::ATOM);
 		$logTimeZone = $config->getValue('logtimezone', 'UTC');
 		try {
 			$timezone = new \DateTimeZone($logTimeZone);