diff --git a/lib/Service/Appointments/TimezoneGenerator.php b/lib/Service/Appointments/TimezoneGenerator.php
index 8d7ac406d..aa21f9569 100644
--- a/lib/Service/Appointments/TimezoneGenerator.php
+++ b/lib/Service/Appointments/TimezoneGenerator.php
@@ -47,14 +47,6 @@ public function generateVtimezone(string $timezone, int $from, int $to): ?VTimeZ
 		$standard = $daylightStart = null;
 		foreach ($transitions as $i => $trans) {
 			$component = null;
-
-			// skip the first entry...
-			if ($i === 0) {
-				// ... but remember the offset for the next TZOFFSETFROM value
-				$tzfrom = $trans['offset'] / 3600;
-				continue;
-			}
-
 			// daylight saving time definition
 			if ($trans['isdst']) {
 				$daylightDefinition = $trans['ts'];
@@ -69,9 +61,15 @@ public function generateVtimezone(string $timezone, int $from, int $to): ?VTimeZ
 			}
 
 			if ($component) {
-				$date = new \DateTime($trans['time']);
-				$offset = $trans['offset'] / 3600;
-
+				if ($i === 0) {
+					$date = new \DateTime('19700101T000000');
+					$tzfrom = $trans['offset'] / 3600;
+					$offset = $tzfrom;
+				} else {
+					$date = new \DateTime($trans['time']);
+					$offset = $trans['offset'] / 3600;
+				}
+				
 				$component->DTSTART = $date->format('Ymd\THis');
 				$component->TZOFFSETFROM = sprintf('%s%02d%02d', $tzfrom >= 0 ? '+' : '-', abs(floor($tzfrom)), ($tzfrom - floor($tzfrom)) * 60);
 				$component->TZOFFSETTO = sprintf('%s%02d%02d', $offset >= 0 ? '+' : '-', abs(floor($offset)), ($offset - floor($offset)) * 60);
diff --git a/tests/php/unit/Service/Appointments/TimezoneGeneratorTest.php b/tests/php/unit/Service/Appointments/TimezoneGeneratorTest.php
index 0f8ea764b..68b76c2af 100644
--- a/tests/php/unit/Service/Appointments/TimezoneGeneratorTest.php
+++ b/tests/php/unit/Service/Appointments/TimezoneGeneratorTest.php
@@ -43,7 +43,7 @@ public function testNoDaylightSaving($timezone, $daytime, $standard, $msTimezone
 
 		$this->assertEquals($timezone, $generated->TZID->getValue());
 		$this->assertNull($generated->DAYLIGHT);
-		$this->assertNull($generated->STANDARD);
+		$this->assertNotNull($generated->STANDARD);
 		$this->assertEquals($generated->{'X-MICROSOFT-CDO-TZID'}->getValue(), $msTimezoneId);
 	}
 
@@ -57,17 +57,17 @@ public function testInvalid(): void {
 	public function providerDaylightSaving(): array {
 		$microsoftExchangeMap = array_flip(TimeZoneUtil::$microsoftExchangeMap);
 		return [
-			['Europe/Berlin', 3, 3, $microsoftExchangeMap['Europe/Berlin']],
-			['Europe/London', 3, 3, $microsoftExchangeMap['Europe/London']],
-			['Australia/Adelaide', 3, 3, $microsoftExchangeMap['Australia/Adelaide']],
+			['Europe/Berlin', 3, 4, $microsoftExchangeMap['Europe/Berlin']],
+			['Europe/London', 3, 4, $microsoftExchangeMap['Europe/London']],
+			['Australia/Adelaide', 4, 3, $microsoftExchangeMap['Australia/Adelaide']],
 		];
 	}
 
 	public function providerNoDaylightSaving(): array {
 		$microsoftExchangeMap = array_flip(TimeZoneUtil::$microsoftExchangeMap);
 		return [
-			['Pacific/Midway', null, null, $microsoftExchangeMap['Pacific/Midway']],
-			['Asia/Singapore', null, null, $microsoftExchangeMap['Asia/Singapore']],
+			['Pacific/Midway', null, 1, $microsoftExchangeMap['Pacific/Midway']],
+			['Asia/Singapore', null, 1, $microsoftExchangeMap['Asia/Singapore']],
 		];
 	}