diff --git a/README.md b/README.md
index fed8c9b..df1fb20 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ Resolve geographical coordinates to timezones and countries. This is a Swift wra
 
 A timezone database with up to 20 meter resolution is embedded as a bundle resource (~5 MB). If you want to manually specify the database location, use `try SwiftTimeZoneLookup(databasePath: "/path_to_timezone16_21_files/..")`
 
-Embedded timezone database version [2023b (2023-03-26)](https://github.com/evansiroky/timezone-boundary-builder/releases/tag/2023b).
+Embedded timezone database version [2023d (2023-12-29)](https://github.com/evansiroky/timezone-boundary-builder/releases/tag/2023d).
 
 This library is thread safe.
 
diff --git a/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin b/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin
index e49583f..a1e0440 100644
Binary files a/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin and b/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin differ
diff --git a/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin b/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin
index db5f13e..b1db4e8 100644
Binary files a/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin and b/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin differ