> some Element users are still stuck on the Classic app, unaware that Element X exists

This sounds really arrogant. Element X _still_ lacks a lot of features, saying that the only reason to use classic Element is that you must be unaware of Element X completely ignores that. I wish “Element Creations Ltd” was as aggressive in creating Element X as they are in pushing it.

what are you missing? the only things i can think of now are live location sharing, and a thread index?

According to the official Matrix website (https://matrix.org/ecosystem/clients/element-x/, https://matrix.org/ecosystem/clients/element/): threads, voice calls, spaces, SSO.

the “official matrix website” is basically a wiki that people happen to have PR’d against; it’s updated best effort.

In practice EX has threads, 1:1 calls, spaces and SSO now (threads and spaces in labs, as per the OP, but usable)

At least a while ago Element X broke bridging in a pretty annoying way, since all chats with more than 2 members were classified as groups, even if they were marked as DMs.