An AWS team member mentioned to me on Twitter that the DocumentDB project at Amazon began more than two years ago. Mongo may or may not have known about it directly, but even if they didn’t, they had to expect it.

The difference between AGPLv3 and the new SSPL applies to all work Mongo releasaes going forward. As intended, that difference will make it difficult for AWS to maintain compatibility, which the article points out is limited from the get-go.