diff --git a/lib/timezonedata/php-bc.php b/lib/timezonedata/php-bc.php
index bd60f26d..44248da7 100644
--- a/lib/timezonedata/php-bc.php
+++ b/lib/timezonedata/php-bc.php
@@ -31,6 +31,7 @@
     'America/Pangnirtung',
     // Moved to backward in 2023a
     'America/Yellowknife',
+    'Asia/Choibalsan',
 
     // Original list
     'Africa/Asmera',