ICU 73

ICU is the premier library for software internationalization, used by a wide array of companies and organizations.

Release Overview

Note: The ICU 73.2 maintenance update (see below) was released on 2023-06-15.

ICU 73 updates to CLDR 43 (blog) locale data with various additions and corrections.

ICU 73 improves Japanese and Korean short-text line breaking, reduces C++ memory use in date formatting, and promotes the Java person name formatter from tech preview to draft.

ICU 73 updates to the time zone data version 2023c (March 2023). Note that pre-1970 data for a number of time zones has been removed, as has been the case in the upstream tzdata release since 2021b.

For more details, including migration issues, see below.

Please use the icu-support mailing list and/or find/submit error reports.

Version Number

The initial release has library version number 73.1.

If there are maintenance releases, they will be 73.2, 73.3, etc. (During ICU 73 development, the library version number was 73.0.x.)

Note: There may be additional commits on the maint/maint-73 branch that are not included in the prepackaged download files.

ICU 73.2 maintenance release

Release date: 2023-06-15

ICU 73.2 updates to CLDR 43.1 locale data. These are maintenance releases for ICU 73 and CLDR 43, with limited sets of bug fixes and no API or structural changes.

There are significant changes for GB18030-2022 compliance support:

There are also changes for compatibility:

ICU 73.2 and CLDR 43.1 include several other bug fixes, including person name formatting, and Cyrillic transforms.

Next Release (FYI)

For the next release, ICU 74 in 2023-oct, we plan to make the following changes:

Common Changes

ICU4C Specific Changes

Some internal changes:

ICU4J Specific Changes

Known Issues


Migration Issues

ICU4C Platform Support

ICU4C requires C++11 and has been tested with up to C++20.

We routinely test on recent versions of Linux, macOS, and Windows.

We accept patches for other platforms.

Windows: The minimum supported version is Windows 7. (See How To Build And Install On Windows for more details.)

ICU4J Platform Support

ICU4J works on Java 8..17.

ICU4J should work on Android API level 21 and later but may require “library desugaring”.


Source and binary downloads are available on the git/GitHub tag page:

See the Source Code Access page for how to download the ICU file tree directly from GitHub.

ICU locale data was generated from the CLDR tag:

Maven dependency: