CLDR 49 Release Note
| No. | Date | Rel. Note | Data | Charts | Spec | Delta | GitHub Tag | Delta DTD | CLDR JSON |
|---|---|---|---|---|---|---|---|---|---|
| 49 | 2026-03- |
v49 | Charts49 | LDML49 | Δ49 | ΔDtd48 |
Overview
Unicode CLDR provides key building blocks for software supporting the world’s languages. CLDR data is used by all major software systems (including all mobile phones) for their software internationalization and localization, adapting software to the conventions of different languages.
Changes
The most significant changes in this release are:
- TBD
For more details, see below.
Locale Coverage Status
Current Levels
| Count | Level | Usage | Examples |
|---|---|---|---|
| xx | Modern | Suitable for full UI internationalization | … |
| xx | Moderate | Suitable for “document content” internationalization, eg. in spreadsheet | … |
| xx | Basic | Suitable for locale selection, eg. choice of language on mobile phone | … |
Changes
| ± | New Level | Locales |
|---|---|---|
| 📈 | Modern | … |
| 📈 | Moderate | … |
| 📈 | Basic | … |
| 📉 | Basic* | … |
* Note: Each release, the number of items needed for Modern and Moderate increases. So locales without active contributors may drop down in coverage level.
For a full listing, see Coverage Levels
Specification Changes
The following are the most significant changes to the specification (LDML).
- TBD
There are many more changes that are important to implementations, such as changes to certain identifier syntax and various algorithms. See the Modifications section of the specification for details.
Data Changes
DTD Changes
- TBD
For a full listing, see Delta DTDs.
Supplemental Data Changes
- TBD
For a full listing, see ¤¤BCP47 Delta and ¤¤Supplemental Delta
Locale Changes
- TBD
For a full listing, see Delta Data
Message Format Specification
- TBD
Collation Data Changes
- TBD
Number Spellout Data Changes
- TBD
Segmentation Data Changes
- TBD
Transform Data Changes
- TBD
JSON Data Changes
- TBD
File Changes
- TBD
Tooling Changes
- TBD
Keyboard Changes
- TBD
Migration
- TBD
V49 advance warnings
The following changes are planned for CLDR 49. Please plan accordingly to avoid disruption.
- H24 will be deprecated. If it is encountered, it will have H23 behavior. There is no known intentional usage of H24. If you have a current need for H24 instead of H23, please comment on CLDR-18303.
- As of CLDR 49, the default week numbering system will change to follow ISO (where weeks are numbered based on Thursday), instead of being based on the start of the calendar week. The calendar week will be more clearly targeted at matching usage in displayed month calendars. CLDR-18275
- The pre-Meiji Japanese eras will be removed: There was too much uncertainty in the exact values and feedback that the general practice for exact dates is to use Gregorian for pre-Meiji dates.
- The major components in supplementalData.xml and supplementalMetadata.xml files are slated to be organized more logically and moved into separate files.
- This will make it easier for implementations to filter out data that they don’t need, and make internal maintenance easier. This will not affect the data, just which file it is located in. Please plan to update XML and JSON parsers accordingly.
Known Issues
- ISO 3166-2 subdivision codes for Iran changed in 2020, and there are not yet new equivalent stable codes. See CLDR-19046 for more details.
Acknowledgments
Many people have made significant contributions to CLDR and LDML; see the Acknowledgments page for a full listing.
The Unicode Terms of Use apply to CLDR data; in particular, see Exhibit 1.
For web pages with different views of CLDR data, see http://cldr.unicode.org/index/charts.