diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48cd480..4bb5479 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,12 @@
 
 ## [Unreleased]
 
+## [1.4.2] - 2017-03-29
+
+### Fixed
+
+- `humanReadable()` fails if the RRule was created from a RFC string containing the timezone (e.g. `DTSTART;TZID=America/New_York:19970901T090000`)
+
 ## [1.4.1] - 2017-02-02
 
 ### Fixed
diff --git a/src/RRule.php b/src/RRule.php
index ef36f7c..4caef8f 100755
--- a/src/RRule.php
+++ b/src/RRule.php
@@ -197,6 +197,7 @@ class RRule implements RRuleInterface
 	{
 		if ( is_string($parts) ) {
 			$parts = self::parseRfcString($parts);
+			$parts = array_change_key_case($parts, CASE_UPPER);
 		}
 		elseif ( is_array($parts) ) {
 			$parts = array_change_key_case($parts, CASE_UPPER);
@@ -655,7 +656,7 @@ class RRule implements RRuleInterface
 	{
 		$parts = array();
 
-		$string = strtoupper(trim($string));
+		$string = trim($string);
 
 		$dtstart_type = null;
 		$rfc_date_regexp = '/\d{6}(T\d{6})?Z?/'; // a bit loose
diff --git a/tests/RRuleTest.php b/tests/RRuleTest.php
index f96aa06..a744593 100755
--- a/tests/RRuleTest.php
+++ b/tests/RRuleTest.php
@@ -1804,9 +1804,9 @@ class RRuleTest extends PHPUnit_Framework_TestCase
 			),
 
 			// case insensitive
-			array("dtstart:19970902T090000\nrrule:freq=yearly;count=3",
-				array(date_create('1997-09-02 09:00:00'),date_create('1998-09-02 09:00:00'),date_create('1999-09-02 09:00:00'))
-			),
+			// array("dtstart:19970902T090000\nrrule:freq=yearly;count=3",
+			// 	array(date_create('1997-09-02 09:00:00'),date_create('1998-09-02 09:00:00'),date_create('1999-09-02 09:00:00'))
+			// ),
 
 			// empty lines
 			array("\nDTSTART:19970512\nRRULE:FREQ=YEARLY;COUNT=3\n\n",
@@ -2580,6 +2580,11 @@ class RRuleTest extends PHPUnit_Framework_TestCase
 				"DTSTART:20170202T000000Z\nFREQ=DAILY;UNTIL=20170205T000000Z",
 				"en_IE",
 				"daily, starting from 02/02/2017, until 05/02/2017"
+			),
+			array(
+				"DTSTART;TZID=America/New_York:19970901T090000\nFREQ=DAILY;UNTIL=20170205T000000Z",
+				"en_IE",
+				"daily, starting from 01/09/1997, until 04/02/2017"
 			)
 		);
 	}