https://github.com/jupyterhub/jupyterlab-hub/issues/44

It… could be a memory issue?

error: The option `services.matrix-synapse.settings.listeners.[definition 1-entry 1].bind_address' does not exist. Definition values:
       - In `/etc/nixos/configuration.nix': "127.0.0.1"
(use '--show-trace' to show detailed location information)

Did I misinterpret the latest release config that all top-level config things should be moved to the settings. section?

The listeners.*.bind_address option was renamed to bind_addresses in order to match the upstream homeserver.yaml option name. It is now also a list of strings instead of a string.

I ran into another issue though.
I naively just added a settings = { indented my old config lines and closed the curly braces.
This was valid enough to build but had multiple issuss:

database_args was accepted but did not work as expected. This lead to my database name below that being ignored.
Fix was easy, make it database.args and it is ok.
Another thing which broke was my old extraConfig which ended up as a single line in the new config.

I feel this was not sufficiently documented. For such a major change I'd hope for more safeguards or a much more detailed release notes entry that actually covers all those cases.

need to be moved into services.matrix-synapse.settings

might have kind of implied you could just copy it in. but how settings (RFC42) works in the rest of nixos should make it somewhat a pattern so people hopefully don't actually verbatimely copy things into the settings

I don't think there's a nice way to sanity check freeform settings in general (since you want to be able to specify their contents freely), but maybe we could have explicitly checked for things like database_args for a while and thrown