Renaming thirty-one regions without breaking anyone
Ninety days of notice, a deprecation header on every affected call, and both schemes live at once. It is the only breaking change we shipped this year.
The old region names were us-east, eu-west, ap-south and so on. That scheme has one fatal property: it cannot express two regions in the same metro. We now have that in three places, and were about to have it in a fourth.
How the change was shipped
Both schemes resolve. Requests using an old name are served normally and come back with a Deprecation header carrying the sunset date and the new name. The old names stop resolving on 9 September 2026, ninety days after the announcement, which is the notice period we committed to and have never shortened.
What we would do differently
The mapping is not one-to-one — us-east became iad1, but there are now also ewr1 and ord1 that used to be inside it. A client that pinned us-east for residency reasons was pinning a larger area than it thought, and the new scheme narrows it. We should have said that in the first paragraph of the announcement rather than the fifth.