[somebehemoth]

Are both versions of their apps open source and do they have equivalent features? Second question (maybe based upon old info) but I thought deleting email from GMail does not really delete the email which is retained for Google's purposes? These are sincere questions and not intended to be rhetorical.

[techrat]

Equivalent features that are not tied into Google services? Yes. Messenger does MMS/SMS. So does Hangouts. I don't think it's unreasonable to expect that specific services (Voice calling over GTalk) should require the specific app (Hangouts)

And no, Google does not keep emails. After 30 days you cannot recover anything.

https://support.google.com/a/answer/112445?hl=en

>If you can't find your messages in All Mail, Spam, or Trash, or by performing a search, then they've been permanently removed from Gmail, possibly deleted by someone else. We regret that we are unable to recover messages that have been permanently deleted.

I can confirm that having emails permanently deleted, such as when I unsubscribed from mailings from a store I deleted my account from... I stopped receiving advertisements in the sidebar related to that store. When you stop getting ads about specific things after deleting all emails about those specific things, I would say that's fairly conclusive.