Newbie questions

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@uhgwt436

Not sure how to reply to your reply using the nice format you used where the reply is interspersed with the questions…

You can select part of the text, then click “quote” appearing near selection.

@uhgwt436

There might be a bug here since the name of the sender only showed up on 1 of 4 devices. On the other three I had to add/edit the name of the contact myself.

Could it be that it is the only device which has the name in the address book? Did you give address book access to Delta Chat? Just in case, Delta Chat never sends the addresses collected from the address book anywhere, only displays them in the list of contacts.

@uhgwt436

Noted about message size and that the e-mail providers’ limits might come into play. Somewhere in the back of my head I remember something about an RFC only requiring message sizes up to 10 MB?

I’m not aware of this, and in practice it is possible to send messages more than 10 MiB, so no reason to change this limit.

@uhgwt436

But, one solution could be that larger files are automatically split into multiple encrypted messages and then reassembled on the recipient’s system? (And of course, on any other devices the sender also has.) This would allow program files/videos etc etc to be shared seamlessly.

There is a support for fragmentation in MIME format, but it is not implemented: RFC 2046 - Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types The idea is simple, split the message into numbered fragments, collect them in a separate database table, and once the message can be reassembled, process it as a whole. This could be a separate feature request.

@uhgwt436

I plan to use DC only for encrypted messages, at least for now, so I will only accept contact requests from other DC users (or other compatible AutoCrypt systems).

If you have the setting “Show classic emails” set to “No, chats only”, then Delta Chat will only show messages from other Delta Chat clients and they are almost always encrypted unless one of the user requests to disable encryption explicitly.

@uhgwt436

On that note, if someone gets access to my mail provider’s backend (or the other party’s backend server), will they be able to read old messages?

They will be able to see what you see in the web interface. This means first unencrypted messages. If you want, you can enable message deletion from the server, say “after 4 weeks” (“after 5 weeks” in the new versions of DC) in the settings, so messages are deleted eventually, but make sure to make this time span large enough for your other devices to pick up the messages. You can also use “disappearing messages” feature per-chat, it will enable deletion on the other side too (unless they disagree and disable it back).

@uhgwt436

With the four systems, I have carefully watched to see if notifications show up on all four systems which would be expected and that is /not/ the case. Typically 3 of 4 systems show notification messages although even the system that does not show a notification message is up to date with messages.

How did you find the device which did not show notification has got the message? Maybe it downloaded the message only when you opened the app? If notifications don’t work reliable, you can try to enable “permanent notification” in the settings (assuming you are on android), it sometimes prevent the app from being killed or at least lets you see if the app is running. Could be that the app is killed, see https://dontkillmyapp.com/ It is usually ok for apps that use Google services for notifications, but not ok for Delta Chat, XMPP clients etc. who maintain their own network connections.

@uhgwt436

Also, reading new messages on a device does not remove the notification prompt on the other devices. Is it possible that there is some sync issue between each device and the IMAP backend?

This is currently not implemented. We can watch for the flags change and remove the notification if message is marked as seen, but currently Delta Chat also marks the message as seen on the server even before you read it. The logic should be revised here to mark the message as seen when you read it, and remove notification when IMAP says some other device has marked the message as seen.

@uhgwt436

I have also surprisingly noticed that deleting a message on one device does not automatically delete it on the other devices which is what one would expect since all devices should be fully synced. This can hardly be as designed. Could this be a sync issue?

This is by design, IMAP is used as a “feed”, we download messages from it but don’t rely on them being stored on the server afterwards. Some users have low quota on the server and periodically delete or archive to local disk all messages there, in which case we still want to store messages in Delta Chat. “Delete message” feature deletes locally and on the server, but not on the other devices.

@uhgwt436

I forgot to add that one of the incoming messages was filtered to the spam-folder outside DC. This is not the fault of DC, of course, but something one should be aware of and monitor, either manually or disabling spam-checking on the e-mail account entirely.

Newer versions of DC (nightly builds for Android and next releases) check the Spam folder periodically. There is also a plan to start watching the folders in which messages arrive: Improve scanning folders · Issue #2140 · deltachat/deltachat-core-rust · GitHub So eventually the problem will be resolved without the need to do anything on the user/provider side.