conversations-classic/README.md

Conversations Classic

Conversations Classic: the very last word in instant messaging

Design principles

• Be as beautiful and easy to use as possible without sacrificing security or privacy
• Rely on existing, well established protocols (XMPP)
• Do not require a Google Account or specifically Google Cloud Messaging (GCM)

Features

• End-to-end encryption with OMEMO or OpenPGP
• Send and receive images as well as other kind of files
• Encrypted audio and video calls (DTLS-SRTP) with DTMF dialer support
• Share your location
• Send voice messages
• Indication when your contact has read your message
• Intuitive UI that follows Android Design guidelines
• Pictures / Avatars for your Contacts
• Synchronizes with desktop client
• Conferences (with support for bookmarks)
• Address book integration
• Multiple accounts / unified inbox
• Very low impact on battery life

XMPP Features

Conversations Classic works with every XMPP server out there. However XMPP is an extensible protocol. These extensions are standardized as well in so called XEP's. Conversations Classic supports a couple of these to make the overall user experience better. There is a chance that your current XMPP server does not support these extensions; therefore to get the most out of Conversations Classic you should consider either switching to an XMPP server that does or — even better — run your own XMPP server for you and your friends. These XEP's are:

• XEP-0065: SOCKS5 Bytestreams will be used to transfer files if both parties are behind a firewall (NAT).
• XEP-0163: Personal Eventing Protocol for avatars and OMEMO.
• XEP-0191: Blocking command lets you blacklist spammers or block contacts without removing them from your roster.
• XEP-0198: Stream Management allows XMPP to survive small network outages and changes of the underlying TCP connection.
• XEP-0215: External Service Discovery will be used to discover STUN and TURN servers which facilitate P2P A/V calls.
• XEP-0280: Message Carbons which automatically syncs the messages you send to your desktop client and thus allows you to switch seamlessly from your mobile client to your desktop client and back within one conversation.
• XEP-0237: Roster Versioning mainly to save bandwidth on poor mobile connections
• XEP-0313: Message Archive Management synchronize message history with the server. Catch up with messages that were sent while Conversations Classic was offline.
• XEP-0308: Last Message Correction allows you to edit last message as well as retract it
• XEP-0352: Client State Indication lets the server know whether or not Conversations is in the background. Allows the server to save bandwidth by withholding unimportant packages.
• XEP-0363: HTTP File Upload allows you to share files in conferences and with offline contacts.
• XEP-0461: Message Replies provides support of native replies, which also works in many transports (gateways) as well

FAQ

General

How do I install Conversations?

Conversations Classic is entirely open source and licensed under GPLv3. So if you are a software developer you can check out the sources from GitHub and use Gradle to build your apk file.

How do I create an account?

XMPP, like email, is a federated protocol, which means that there is not one company you can create an official XMPP account with. Instead there are hundreds, or even thousands, of providers out there. One of those providers is conversations.im. If you don’t like to use conversations.im use a web search engine of your choice to find another provider. Or maybe your university has one. Or you can run your own. Or ask a friend to run one. Once you've found one, you can use Conversations to create an account. Just select register new account on server within the create account dialog.

Domain hosting

Using your own domain not only gives you a more recognizable Jabber ID, it also gives you the flexibility to migrate your account between different XMPP providers. This is a good compromise between the responsibilities of having to operate your own server and the downsides of being dependent on a single provider.

Running your own

If you already have a server somewhere and are willing and able to put the necessary work in you can run your own XMPP server.

As of 2023 XMPP has reached a level of maturity where all major XMPP servers (ejabberd, Prosody, Openfire, Tigase) should work well with Conversations.

Interoperability with Prosody and ejabberd is tested fairly regularly just because of their market share but we occasionally test with other servers too and fix issues as soon as we are being made aware of them.

Where can I set up a custom hostname / port

Conversations Classic will automatically look up the SRV records for your domain name which can point to any hostname port combination. If your server doesn’t provide those please contact your admin and have them read this. If your server operator is unwilling to fix this you can enable advanced server settings in the expert settings of Conversations Classic.

I get 'Incompatible Server'

As regular user you should be picking a different server. The server you selected is probably insecure and/or very old.

If you are a server administrator you should make sure that your server provides either STARTTLS or XEP-0368: SRV records for XMPP over TLS.

On rare occasions this error message might also be caused by a server not providing a login (SASL) mechanism that Conversations Classic is able to handle. Conversations Classic supports SCRAM-SHA1, PLAIN, EXTERNAL (client certs) and DIGEST-MD5.

I get 'Bind failure'. What does that mean?

Some Bind failures are transient and resolve themselves after a reconnect.

When trying to connect to OpenFire the bind failure can be a permanent problem when the domain part of the Jabber ID entered in Conversations Classic doesn’t match the domain the OpenFire server feels responsible for. For example OpenFire is configured to use the domain a.tld but the Jabber ID entered is user@b.tld where b.tld also points to the same host. During bind OpenFire tries to reassign the Jabber to user@a.tld. Conversations Classic doesn’t like that. This can be fixed by creating a new account in Conversations Classic that uses the Jabber ID user@a.tld.

Note: This is kind of a weird quirk in OpenFire. Most other servers would just throw a 'Server not responsible for domain' error instead of attempting to reassign the Jabber ID.

Maybe you attempted to use the Jabber ID test@b.tld because a.tld doesn’t point to the correct host. In that case you might have to enable the extended connection settings in the expert settings of Conversations and set a host name.

I get 'Stream opening error'. What does that mean?

In most cases this error is caused by ejabberd advertising support for TLSv1.3 but not properly supporting it. This can happen if the OpenSSL version on the server already supports TLSv1.3 but the fast_tls wrapper library used by ejabberd not (properly) support it. Upgrading fast_tls and ejabberd or - theoretically - downgrading OpenSSL should fix the issue. A work around is to explicitly disable TLSv1.3 support in the ejabberd configuration. More information can be found on this issue on the ejabberd issue tracker.

The battery consumption and the entire behavior of Conversations Classic will remain the same (as good or as bad as it was before). Why is Google doing this to you? We have no idea.

Android <= 7.1 or Conversations Classic from F-Droid (all Android versions)

The foreground notification is still controlled over the expert settings within Conversations Classic as it always has been. Whether or not you need to enable it depends on how aggressive the non-standard 'power saving' features are that your phone vendor has built into the operating system.

Android 8.x

Long press the permanent notification and disable that particular type of notification by moving the slider to the left. This will make the notification disappear but create another notification (this time created by the operating system itself.) that will complain about Conversations (and other apps) using battery. Starting with Android 8.1 you can disable that notification again with the same method described above.

Android 9.0+

Long press the permanent notification and press the info (i) button to get into the App info screen. In that screen touch the 'Notification' entry. In the next screen remove the checkbox for the 'Foreground service' entry.

Conversations doesn’t work for me. Where can I get help?

You can join our conference room on xmppclient-dev@conference.narayana.im. A lot of people in there are able to answer basic questions about the usage of Conversations Classic or can provide you with tips on running your own XMPP server. If you found a bug or your app crashes please read the Developer / Report Bugs section of this document.

How does the address book integration work?

The address book integration was designed to protect your privacy. Conversations Classic neither uploads contacts from your address book to your server nor fills your address book with unnecessary contacts from your online roster. If you manually add a Jabber ID to your phones address book Conversations Classic will use the name and the profile picture of this contact. To make the process of adding Jabber IDs to your address book easier you can click on the profile picture in the contact details within Conversations Classic. This will start an "add to address book" intent with the JID as the payload. This doesn't require Conversations Classic to have write permissions on your address book but also doesn't require you to copy/paste a JID from one app to another.

I get 'delivery failed' on my messages

If you get delivery failed on images it's probably because the recipient lost network connectivity during reception. In that case you can try it again at a later time.

For text messages the answer to your question is a little bit more complex. When you see 'delivery failed' on text messages, it is always something that is being reported by the server. The most common reason for this is that the recipient failed to resume a connection. When a client loses connectivity for a short time the client usually has a five minute window to pick up that connection again. When the client fails to do so because the network connectivity is out for longer than that all messages sent to that client will be returned to the sender resulting in a delivery failed.

Instead of returning a message to the sender both ejabberd and prosody have the ability to store messages in offline storage when the disconnecting client is the only client. In prosody this is available via an extra module called mod_smacks_offline. In ejabberd this is available via some configuration settings.

Other less common reasons are that the message you sent didn't meet some criteria enforced by the server (too large, too many). Another reason could be that the recipient is offline and the server doesn't provide offline storage.

Usually you are able to distinguish between these two groups in the fact that the first one happens always after some time and the second one happens almost instantly.

Where can I see the status of my contacts? How can I set a status or priority?

Statuses are a horrible metric. Setting them manually to a proper value rarely works because users are either lazy or just forget about them. Setting them automatically does not provide quality results either. Keyboard or mouse activity as indicator for example fails when the user is just looking at something (reading an article, watching a movie). Furthermore automatic setting of status always implies an impact on your privacy (are you sure you want everybody in your contact list to know that you have been using your computer at 4am‽).

In the past status has been used to judge the likelihood of whether or not your messages are being read. This is no longer necessary. With Chat Markers (XEP-0333, supported by Conversations since 0.4) we have the ability to know whether or not your messages are being read. Similar things can be said for priorities. In the past priorities have been used (by servers, not by clients!) to route your messages to one specific client. With carbon messages (XEP-0280, supported by Conversations since 0.1) this is no longer necessary. Using priorities to route OTR messages isn't practical either because they are not changeable on the fly. Metrics like last active client (the client which sent the last message) are much better.

Unfortunately these modern replacements for legacy XMPP features are not widely adopted. However Conversations Classic should be an instant messenger for the future and instead of making Conversations Classic compatible with the past we should work on implementing new, improved technologies and getting them into other XMPP clients as well.

Making these status and priority optional isn't a solution either because Conversations Classic is trying to get rid of old behaviours and set an example for other clients.

How do I backup / move Conversations Classic to a new device?

Use the Backup button in the Settings.

Conversations Classic is missing a certain feature

Please report it to our XMPP conference xmppclient-dev@conference.narayana.im

Security

Why are there two end-to-end encryption methods and which one should I choose?

• OMEMO works even when a contact is offline, and works with multiple devices. It also allows asynchronous file-transfer when the server has HTTP File Upload. However, OMEMO not widely support and is currently implemented only by a handful of clients.
• OpenPGP (XEP-0027) is a very old encryption method that has some advantages over OMEMO but should only be used by people who know what they are doing.

How do I use OpenPGP

Before you continue reading you should note that the OpenPGP support in Conversations Classic is experimental. This is not because it will make the app unstable but because the fundamental concepts of PGP aren't ready for widespread use. The way PGP works is that you trust Key IDs instead of JID's or email addresses. So in theory your contact list should consist of Public-Key-IDs instead of JID's. But of course no email or XMPP client out there implements these concepts. Plus PGP in the context of instant messaging has a couple of downsides: It is vulnerable to replay attacks and it is rather verbose.

To use OpenPGP you have to install the open source app OpenKeychain and then long press on the account in manage accounts and choose renew PGP announcement from the contextual menu.

OMEMO is grayed out. What do I do?

OMEMO is only available in 1:1 chats and private (members-only, non-anonymous) group chats. Encrypting public group chats makes little to no sense since anyone (including a hypothetical attacker) can join and a user couldn’t possibily verify all participants anyway. Furthermore for a lot of public group chat it is desirable to give new comers access to the full history.

OMEMO doesn’t work. I get a 'Something went wrong' message in the 'Trust OMEMO Fingerprints' screen.

OMEMO has two requirements: Your server and the server of your contact need to support PEP. Both of you can verify that individually by opening your account details and selecting Server info from the menu. The appearing table should list PEP as available. The second requirement is that the initial sender needs to have access to the published key material. This can either be achieved by having mutual presence subscription (you can verify that by opening the contact details and see if both check boxes Send presence updates and Receive presence updates are checked) or by using a server that makes the public key material accessible to anyone. In the Compliance Tester this is indicated by the 'OMEMO' feature. Since it is very common that the first messages are exchanged before adding each other to the contact list it is desirable to use servers that have 'OMEMO support'.

How does the encryption for group chats work?

OMEMO

OMEMO encryption works only in private (members only) conferences that are non-anonymous. Non-anonymous (being able to discover the real JID of other participants) is a technical requirement to discover the key material. Members only is a sort of arbitrary requirement imposed by Conversations. (see 'OMEMO is grayed out')

The server of all participants need to pass the OMEMO Compliance Test. In other words they either need to run ejabberd 18.01+ or Prosody 0.11+.

(Alternatively it would also work if all participants had each other in their contact list; But that rarely is the case in larger group chats.)

The owner of a conference can make a public conference private by going into the conference details and hit the settings button (the one with the gears) and select both private and members only.

OpenPGP

Every participant has to announce their OpenPGP key (see answer above). If you would like to send encrypted messages to a conference you have to make sure that you have every participant's public key in your OpenKeychain. Right now there is no check in Conversations Classic to ensure that. You have to take care of that yourself. Go to the conference details and touch every key id (The hexadecimal number below a contact). This will send you to OpenKeychain which will assist you on adding the key. This works best in very small conferences with contacts you are already using OpenPGP with. This feature is regarded experimental. Conversations Classic is the only client that uses XEP-0027 with conferences. (The XEP neither specifically allows nor disallows this.)

What is Blind Trust Before Verification / why are messages marked with a red lock?

Read more about the concept on https://gultsch.de/trust.html

I found a bug

Please report it to our XMPP conference xmppclient-dev@conference.narayana.im.