Why history messages are not visible to invited users in encrypted rooms even after settings says it should

[MrJai]

Steps to reproduce

Background:

We are trying to implement a mobile app with end-to-end encryption but providing past messages history to new members joining the group is a key thing we need.

Plan:

We were planning to use olm/megolm and matrix-SDK, and then we tried to test our use cases with Element.io (web, desktop, ios, android) versions.

Issue:

History wasn’t available for new users in a room. Since then we have been studying it, the documentation says it should work by sharing keys, but it is not working with Element clients. We have tried all possibilities of inviting a user from different clients and then accepting the invitation from different clients but the new user is either not able to see the history at all or it is broken (like some messages say keys are not shared, or not possible to show).

We are following these issues from different related repositories, they are also talking about similar or same issues and are not able to fix the issue, but we are not sure what are the reasons for not being able to fix/implement this feature of sharing history with new group member by sharing the keys.

element-web#2286

element-web#2713

matrix-react-sdk#5763

Request:

It will be a huge favour if anyone of you can document the reasons why we have not been able to implement this feature till now, what are the issues that even when the client and the documentation says that it should work, but it is still broken.

Outcome

What did you expect?

Every new member in the end-to-end encrypted private room should be able to see the history when in the settings we have selected "Anyone" for who can watch the history.

What happened instead?

Either it doesn't show anything as if it is a new room and there is no previous message, or it shows waiting for messages/keys, or it shows other warnings/informations but never shows the actual messages.

Operating system

macOS

Application version

Element version: 1.10.1 Olm version: 3.2.8

How did you install the app?

From element.io website I downloaded the dmg file.

Homeserver

matrix.org.

Will you send logs?

No

[dbkr]

This should indeed work - can you provide exact repro steps?

[MrJai]

• create a new private (invite only) room with end-to-end encryption enabled.
• in the settings select Anyone for who can read history.
• send a few messages.
• invite another user b.
• user b should be able read the messages you sent initially, but either those messages are not visible or there information messages on the message timestamps.

From different issues reported on GitHub we noticed that may be the client that is used to send or receive the invitation, can be one of the reasons of different behavior. But we are not sure. We have tried by keeping both user a and b online when sending and accepting invitation but still of no use.

[t3chguy]

@MrJai did you send the few messages AND invite user B from Element Web/Desktop? - are they not hitting #16983 ?

[MrJai]

We are using Element Desktop and Mobile apps mainly for both sending and accepting invite. We hardly used Element web.

[t3chguy]

Element Web/Desktop support this sharing of historical keys, Element mobile does not yet

[MrJai]

Thank you for your response @t3chguy

I have two questions here

• We were definitely using Element Desktop for sending invites, (later on we did try Element Mobile as well), but it didn't work maybe because we were using Element mobile for accepting invites.
• Why this feature is available in Element Web/Desktop and not in Element Mobile. Is there a limitation or is it not possible to share keys from iOS/Android? I am asking this because the product I am planning to develop is a 100% mobile application (at least for now).

[t3chguy]

and not in Element Mobile. Is there a limitation or is it not possible to share keys from iOS/Android? I am asking this because the product I am planning to develop is a 100% mobile application (at least for now).

Just hasn't been implemented yet, you'd need to ask the relevant team (not the element-web tracker) if you have more specific mobile questions however

[p1gp1g]

These steps highlight 2 different problems related to history visibility :

1. Create a private space
2. Invite user2 to the space
3. Create a private room visible to all member
4. Set history visible to all members
5. Join with user2 : the user can't see the history *
6. Redo 1-4 or leave the previous room with user2
7. Invite user2 to the room
8. User2 has to open another room to load the history *

[t3chguy]

@p1gp1g 8. is tracked as a different issue #16983