- Upgrade to tzdata-2025b - New zone for Aysén Region in Chile which moves from -04/-03 to -03. - Paraguay adopted permanent -03 starting spring 2024. - Improve pre-1991 data for the Philippines. - Etc/Unknown is now reserved. - Improve historical data for Mexico, Mongolia, and Portugal. - System V names are now obsolescent. - The main data form now uses %z. - The code now conforms to RFC 8536 for early timestamps. - Support POSIX.1-2024, which removes asctime_r and ctime_r. - Assume POSIX.2-1992 or later for shell scripts. - SUPPORT_C89 now defaults to 1. - Include leap-seconds.list in tzdata install.