diff --git a/lib/timezonedata/exchangezones.php b/lib/timezonedata/exchangezones.php
index 9431db84e..2771ce922 100644
--- a/lib/timezonedata/exchangezones.php
+++ b/lib/timezonedata/exchangezones.php
@@ -21,7 +21,7 @@
     'Brussels, Copenhagen, Madrid, Paris' => 'Europe/Paris',
     'Paris, Madrid, Brussels, Copenhagen' => 'Europe/Paris',
     'Prague, Central Europe' => 'Europe/Prague',
-    'Sarajevo, Skopje, Sofija, Vilnius, Warsaw, Zagreb' => 'Europe/Vilnius',
+    'Sarajevo, Skopje, Sofija, Vilnius, Warsaw, Zagreb' => 'Europe/Sofia',
     'West Central Africa' => 'Africa/Lagos', // This was a best guess
     'Athens, Istanbul, Minsk' => 'Europe/Athens',
     'Bucharest' => 'Europe/Bucharest',
diff --git a/tests/VObject/TimeZoneUtilTest.php b/tests/VObject/TimeZoneUtilTest.php
index dfe94dbd1..e4c5dd853 100644
--- a/tests/VObject/TimeZoneUtilTest.php
+++ b/tests/VObject/TimeZoneUtilTest.php
@@ -675,7 +675,7 @@ public function unSupportTimezoneProvider(): iterable
   "india": "Asia/Kolkata",
   "india standard time": "Asia/Kolkata",
   "indian ocean": "Indian/Chagos",
-  "indiana (east)": "America/New_York",
+  "indiana (east)": "America/Indiana/Indianapolis",
   "indochina": "Asia/Bangkok",
   "indonesia central": "Asia/Makassar",
   "indonesia eastern": "Asia/Jayapura",
@@ -706,7 +706,7 @@ public function unSupportTimezoneProvider(): iterable
   "korea standard time": "Asia/Seoul",
   "kosrae": "Pacific/Kosrae",
   "krasnoyarsk": "Asia/Krasnoyarsk",
-  "kuala lumpur, singapore": "Asia/Shanghai",
+  "kuala lumpur, singapore": "Asia/Singapore",
   "kuybyshev": "Europe/Samara",
   "kwajalein": "Pacific/Kwajalein",
   "kyrgystan": "Asia/Bishkek",
@@ -833,7 +833,7 @@ public function unSupportTimezoneProvider(): iterable
   "samoa standard time": "Pacific/Apia",
   "santiago": "America/Santiago",
   "sao tome standard time": "Africa/Sao_Tome",
-  "sarajevo, skopje, sofija, vilnius, warsaw, zagreb": "Europe/Belgrade",
+  "sarajevo, skopje, sofija, vilnius, warsaw, zagreb": "Europe/Sofia",
   "saratov standard time": "Europe/Saratov",
   "saskatchewan": "America/Edmonton",
   "se asia": "Asia/Bangkok",
@@ -841,8 +841,8 @@ public function unSupportTimezoneProvider(): iterable
   "seoul, korea standard time": "Asia/Seoul",
   "seychelles": "Asia/Dubai",
   "shevchenko": "Asia/Aqtau",
-  "singapore": "Asia/Shanghai",
-  "singapore standard time": "Asia/Shanghai",
+  "singapore": "Asia/Singapore",
+  "singapore standard time": "Asia/Singapore",
   "solomon": "Pacific/Guadalcanal",
   "south africa": "Africa/Maputo",
   "south africa standard time": "Africa/Johannesburg",
@@ -877,13 +877,13 @@ public function unSupportTimezoneProvider(): iterable
   "turkey standard time": "Europe/Istanbul",
   "turkmenistan": "Asia/Ashgabat",
   "turks and caicos standard time": "America/Grand_Turk",
-  "tuvalu": "Asia/Kamchatka",
+  "tuvalu": "Pacific/Tarawa",
   "ulaanbaatar standard time": "Asia/Ulaanbaatar",
   "universal coordinated time": "UTC",
   "uralsk": "Asia/Oral",
   "uruguay": "America/Montevideo",
   "urumqi": "Asia/Urumqi",
-  "us eastern": "America/New_York",
+  "us eastern": "America/Indiana/Indianapolis",
   "us eastern standard time": "America/New_York",
   "us mountain": "America/Phoenix",
   "us mountain standard time": "America/Phoenix",
@@ -908,8 +908,8 @@ public function unSupportTimezoneProvider(): iterable
   "w europe": "Europe/Brussels",
   "w europe standard time": "Europe/Berlin",
   "w mongolia standard time": "Asia/Hovd",
-  "wake": "Asia/Kamchatka",
-  "wallis": "Asia/Kamchatka",
+  "wake": "Pacific/Tarawa",
+  "wallis": "Pacific/Tarawa",
   "west asia": "Asia/Tashkent",
   "west asia standard time": "Asia/Tashkent",
   "west bank standard time": "Asia/Hebron",