IANA Time Zone Database has been upgraded to 2024b. This version mainly includes changes to improve historical data for Mexico, Mongolia, and Portugal. It also changes one timestamp abbreviation, for the time zone 'MET'. Also Asia/Choibalsan is now an alias for Asia/Ulaanbaatar.

The new tzdata changes also impact some legacy zone IDs. Mapping of EST/MST/HST in java.time.ZoneId.SHORT_IDS have changed from fixed offset zones to links to other existing time zones with 2024b. "EST" now links to "America/Panama", "HST" links to "Pacific/Honolulu" and "MST" links to "America/Phoenix". Parsing of the short zone names "EST", "MST", and "HST" is not affected by this change. Further details are available at JDK-8340138