What is the reason that backup of email messages or databse isn't available?

Now, 2024, phone has become very powerful with bigger storage capacity than ever. Many users no longer have a PC and rely on phone solely for their day to day task. Especially on a phone with a desktop mode, one can almost replace the needs of a PC.

As we all know, cloud storage is not secure and reliable. What if you are losing access to your account? You lost all your data when you needed a new phone because no backup is available.

Is there a technical difficulty in implementing a backup of email messages or database? It would be very helpful if we can backup to an external storage via USB OTG.

The server side of IMAP could have gigabytes, perhaps even terabytes, of messages that K-9 only sees a window of. How would such a large stash of data in the cloud get backed up off of a phone?

There are IMAP desktop backup solutions available. I have no experience though.

I’d recommend securing cloud accounts as best as possible: TOTP, push authentication, or passkeys; OAuth, etc.


If a user has terabyte of email then it is a problem of storage management. You can backup then delete on the server. Isn’t K-9 Mail app can download all email messages even if one is using IMAP? Also POP3 exist.

I know there is a backup solution on a PC, however I’m talking about a user that do not own a PC.

Securing a cloud account is not a better solution than an offline backup copy.

K-9 Mail has been designed to manage emails on the server. If you want to download, then remove messages from your mail server, K-9 Mail is not the right tool. This might change at some point in the future. But we have no near-term plans to add this capability.