We [disabled it last year](https://github.com/appsignal/appsignal-elixir/commit/cb7c2e9d607a0035a287db5b7e9485c834fde084), except [we didn't](https://github.com/appsignal/appsignal-elixir/blame/main/lib/appsignal/config.ex#L17). We also [didn't update the docs](https://docs.appsignal.com/elixir/configuration/options.html#option-enable_error_backend). Let's actually do it this time around.