[TheDong]

Their previous consistency was RAW, but not RAU (for most regions. I think us-east-1 was missing RAW consistency for quite a while).

After a write, you would _always_ be able to read the key you just wrote.

After an update, you could get a stale copy of the key if your subsequent read hit a different server.

[heartofgold]

Not quite _always_. There were some documented caveats... the one I hit before was: Read nonexistent key, followed by a write of that same key, and then a subsequent read could return a stale read saying it didn’t exist. (even though it had just been written for the first time.)

Anyway I am glad to see these gaps and caveats have been closed.