Error message for following a tombstone to an unknown room version could be improved

[krille-chan]

Description

I was testing a few scenarios of room upgrades to an unknown room versions (in order to see how quickly we could go use new room versions after they're released in Synapse).

To Reproduce

While testing this for the Element clients I figured I should try FluffyChat too, the following scenarios are what I was looking at:

1. Joining a room
   1. Create a public room on hs1 with room version test
   2. Attempt to join it from hs2
2. Inviting to a room
   1. Create a room on hs1 with room version test
   2. Send an invite to a user on hs2
   3. Attempt to accept the invite
3. Room upgrade
   1. Create a public room on hs1 with room version 6
   2. Join the room as user on hs2
   3. Upgrade the room /upgraderoom test on hs1
   4. Attempt to follow the tombstone.
4. Spaces summary
   1. Create a public room on hs1 with room version test
   2. Create a space and add the above room to it
   3. Send an invite to the space to a user on hs2
   4. Accept the invite
   5. Attempt to explore the space

Note that this somewhat requires hacking a homeserver to have one with an "unknown" room version.

I tested this with FluffyChat web.

Note that I was unable to complete scenarios 1 & 4. (I hadn't used FluffyChat before, but I couldn't figure out if there was a way to join an arbitrary room.)

Scenario 2 completed successfully, the user sees the following:

Scenario 3 gave a generic error message would could be more explicit:

Additional information:

• Device: Chrome or Firefox
• OS and OS version: macOS
• Installed version of FluffyChat: FluffyChat Web (https://fluffychat.im/web/)

Let me know if you have any questions!

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This issue is stale because it has been open for 120 days with no activity.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.