Non-IMAP behavior (now)

Actual behavior

My mail takes up much more space on the server than I have on my device. So I can never see all my emails (or Delta Chat messages) at the same time.

In the case of a regular mail client (for example, K-9 Mail), when checking the mail, a very small part of the message is loaded, and only if necessary, I download the corresponding letter in full.

With Delta Chat, it doesn’t work that way - the messenger loads everything until it runs out of space.

Suppose I select the “delete messages from device after 1 hour” setting in the hope that I can then view the old messages by changing the settings.

But you will no longer be able to view the old messages because there is no way to download them from the server again - just reinstall Delta Chat (but then everything is new on the device will not fit).

Expected behavior

So I ask the developers for either of two possible things (or both at once):

  1. the ability to re-download messages from the server on a specific topic (Delta Chat group) by means of the messenger;
  2. fast loading of several lines of the message , and the rest to download according to a special instruction (action).

This will allow Delta Chat to:

  1. Work with mailboxes larger than the free space on the device.
  2. Use large mailboxes of powerful services like cloud storage (with a management interface via Delta Chat) - the data will be encrypted, easily uploaded and retrieved.

The ability to redownload messages for a particular Delta Chat group requires that server can distinguish between Delta Chat groups. Delta Chat encrypts Subject line and generally strives to reduce the amount of metadata available to the server, probably even to the point of removing the To: field for “Protected groups”.

It probably makes sense to add the ability to redownload +100 old messages or something like this, and the core already has this function for when you setup a new account, but it’s nearly impossible to replicate “cloud messenger” behaviour when everything is on the server and phone is used only as a cache.

Delta Chat also loads only some headers before deciding whether it wants to download the message. But for encrypted messages you can’t say much about the contents, which chat it belongs to etc. without downloading the contents.