ICU 78.2 Released -- and future changes

[Richard Gillam]

Dear clients and friends of ICU—

The ICU 78.2 maintenance release has been released.  This includes all of the changes from CLDR 48.1, along with a few small but important bug fixes.  For details, see the release notes at https://unicode-org.github.io/icu/download/78.html#icu-782-maintenance-release.  To download, see https://github.com/unicode-org/icu/releases/tag/release-78.2.

The planned March release of ICU will be another maintenance release, ICU 78.3, instead of a major release. CLDR is also planning for just a maintenance release in March. The next major release of ICU will be ICU 79, planned for October. It will update to CLDR 49 and Unicode 18.

Attention: Future Changes

Beginning with ICU 79 (October 2026), ICU will be making some significant changes to its API. Please follow the ticket links below for details and to offer comments:

1. We are planning to declare as final C++ classes (such as UnicodeString) that have long been documented as “not suitable for subclassing”. (These are all APIs that existed long before C++ had the final keyword). This change will make the API more resilient, but will break users who have created unsupported subclasses.

   See ICU-23284.

2. CLDR is deprecating the unusual H24 hour cycle, and ICU will change the behavior of H24 to match that of H23. See CLDR-18303.

3. CLDR is removing data and display names for Japanese eras before Meiji. Pre-Meiji dates will be displayed using the Gregorian calendar. See CLDR-11400.

All the best…

—Rich Gillam for the ICU project