Update default HS config to match well-known

[erikjohnston]

We want to move matrix.org client traffic to https://matrix-client.matrix.org

[erikjohnston]

Two things here:

1. Its a little bit of a nuisance that riot-web can't just use the standard well-known for a server name.
2. It would also be nice to have some mechanisms for telling clients they should change where they are talking to, somehow

[turt2live]

Its a little bit of a nuisance that riot-web can't just use the standard well-known for a server name.

We have default_server_name for this

[erikjohnston]

Hmm, the docs say that that is deprecated? Or am I misreading it?

[turt2live]

it does, but so is the thing riot.im has been serving to users for the last decade. It's deprecated because we would prefer people not use it, but ultimately we don't have a proper plan to remove it yet.

[jryans]

@turt2live Do you remember why we finally decided to prefer default_server_config style .well-known in Riot over WK from the HS? There's a use case solved by the Riot one, but I am forgetting what it is...

[erikjohnston]

Any particular reason you'd prefer people not to use it? It seems odd to have a deprecated option that matrix.org ends up using

[jryans]

Indeed... We may want to stop labelling it deprecated if we are going to use it here. Maybe we need to summon @lampholder, as I can't recall if he had one style he'd prefer m.org to use.

[turt2live]

we labelled it deprecated because we eventually don't want to support a bunch of different ways to define a server config. The default_server_config option was chosen as "best" because it has all the features of the other two that people are likely to care about, but misses the auto-updating part of it. It's also the most reliable if there were to be a server problem.

iirc, modular is (or should be) using the new default_server_config option over the other two.

[jryans]

We agreed as a group that default_server_name is the best fit for matrix.org's needs.

We should file a separate feature request to track the desire to switch over active sessions with the HS changes.

[jryans]

Looks good, but please also change:

https://github.com/vector-im/riot-web/blob/d120c3b93e1be2d0cb2e73e47a557d17a49e1fc6/electron_app/riot.im/config.json#L3-L4

[jryans]

Thanks! I'll deploy this to develop now.

[jryans]

Deployed to app / staging as well, looking good. Electron will be updated with the next Riot release (planned for Monday).