We are pleased to announce the release candidate for Unicode® ICU 78. It updates to Unicode 17 (blog), including new characters and scripts, emoji, collation & IDNA changes, and corresponding APIs and implementations.
It also updates to CLDR 48 (beta blog) locale data with new locales, and various additions and corrections.
In Java, there is a draft new Segmenter API which is easier and safer to use than BreakIterator.
In C++, there is a new set of APIs for Unicode string (UTF-8/16/32) code point iteration that works seamlessly with modern C++ iterators and ranges.
The Java implementation of the CLDR MessageFormat 2.0 specification has been updated to CLDR 48. The core API has been upgraded to “draft”, while the Data Model API remains in technology preview.
The C++ implementation of MessageFormat 2.0 is at CLDR 47 level and remains in technology preview.
ICU 78 and CLDR 48 are major releases, including a new version of Unicode and major locale data improvements.
For details, please see https://unicode-org.github.io/icu/download/78.html.
Please test this release candidate on your platforms and report bugs and regressions by Monday, 2025-oct-27, via the icu-support mailing list, and/or please find/submit error reports.
Please do not use this release candidate in production.
The preliminary API reference documents are published on unicode-org.github.io/icu-docs/ – follow the “Dev” links there.