Sources of Time Zone Information
There are just two different sources for Time Zone Information:
The Time Zone Database (often called tz or zoneinfo) contains code and data that represent the history of local time for many representative locations around the globe. It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules. Its management procedure is documented in BCP 175: Procedures for Maintaining the Time Zone Database.
This is the blog maintained by staff at Microsoft to provide general information, announcements and provide answers to Frequently Asked Questions (FAQs) related to daylight saving time (DST) and time zone (TZ) changes around the world.