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## Browser SDK v4 release candidate available

Try version `4.0.0-rc.0` of the SignalWire [Browser SDK](/docs/browser-sdk/guides/overview)
ahead of the stable release. Install it from
[npm](https://www.npmjs.com/package/@signalwire/js) or browse the source on
[GitHub](https://github.com/signalwire/signalwire-js).

## `custom_variables` added to call and message creation

Include `custom_variables` when you create an outbound call with
[Send call commands](/docs/apis/rest/calls/call-commands) or a message with
[Create a message](/docs/apis/rest/messages/create-message). The values are available to your
SWML app while it runs and in your status callbacks, so you can carry your own context, such as
customer IDs or workflow identifiers, through the call or message lifecycle.

## Fixed: Inbound calls and faxes to unconfigured numbers didn't appear in logs

Inbound calls and faxes to phone numbers with no handler configured failed without appearing
in your logs. They now appear with an error that names the missing handler.

![An inbound call log entry with status Failed and an error event with code number\_not\_configured and the message "Inbound call to a number with no call handler configured."](/docs/_fern-files/_img/8d268068fdfbd4f20968d1ba34a9ec186b8c54c4d29ee94c60180b78b530687c.webp)

![An inbound fax log entry with status Failed and a Fax Failed history event reading "Inbound fax to a number with no fax handler configured."](/docs/_fern-files/_img/c1a5545ca1060ce8dbde06e4a41bef87c14d8e612172bf5a5905d25b8f25734b.webp)