This was once common, but it’s somewhat rare now in my experience, and the upcoming Matrix 2.0 apparently addresses most (all?) of the remaining causes.

I still see it - usual case is when someone has two clients. One of them will have issues with this.

I consider this a good thing, for the sake of the people who joined or wrote in the chat with the understanding that what they write is and will remain encrypted. If you want to abandon encryption, you can always create a new room.

Disabling encryption in the room did not have to mean decrypt past history. Yes you can create a new room. But for big groups who wants to risk it. The room admins I know steer clear of encrypted group chats because of the previous issue.

No, there is one officially released client for android: Element. Element X is in beta. When it leaves beta, it will take over as the one officially released client.

One would never guess based on the release announcement

This is just plain false.

https://spec.matrix.org/latest/client-server-api/#sending-encrypted-attachments

The docs say it clearly “If encryption is enabled”. Otherwise attachments are just a link, nothing special there.

Yes and No

I consider matrix to be somewhat equivalent to XMPP or public mailing lists. It is potentially decentralized (even though everyone uses matrix.org) and it can host group chats. And for those purposes it is ok-ish, but for privacy it is no good.

My pet peeve with matrix is that I consider most features to be half baked. And instead of fixing them we just keep pilling up more. Here is a list in no particular order

• encryption regularly breaks in weird ways, usually you see a message that you can’t read
• if you enable encryption in a chat room you cannot disable it
• we now have two official clients for Android (Element and Element X) in the first one encryption breaks in weird ways, in the later there is no way to use Spaces properly
• direct messages between people don’t work well - it is like they are a room with the two people
• privacy wise matrix is weak, leaks metadata, attachments are not encrypted, etc. Do not use if you expect privacy/anonymity. Also I think most groups run without encryption because of the other issues.
• verifying sessions between clients is painful e.g. the client annoys me to verify but then verification does not trigger on the second client

Because of this mess your quality of experience will vary depending on the client and features you use. The web clients are usable.

I don’t really use the video/audio calls so I have no comments on that front.