I'm afraid it's the second paragraph that is the most relevant.
Really, throughout 2015, I was struck by how few updates were made available for both Mailbox and Marvin. By September and October at the latest, Mailbox users started speculating that Dropbox abandoned the software, and yesterday came the awful news that the software was going to be killed mercilessly. And no, they're not going to open-source it; Dropbox is perfectly happy with having flushed $100 million down the toilet only two years ago, and now destroying the hands-down best email software (mobile
or desktop!) on this planet, so that its continued use is made impossible. At the time when Amazon did the same thing to Stanza, Stanza, too, was the world's finest EPUB reader. The parallels are frightening indeed.