# API 1.15

espex 0.10.0 advertises API 1.15 and later. This page covers what 1.15
added.

## What's new

API 1.15 adds `DeviceCapabilitiesRequest`. A client on 1.15 or later
asks for the device's optional features with it and reads them from
`DeviceCapabilitiesResponse`, ignoring the matching `DeviceInfoResponse`
fields:

| `DeviceCapabilitiesResponse` | Replaces in `DeviceInfoResponse` |
|------------------------------|----------------------------------|
| `bluetooth_proxy.feature_flags` | `bluetooth_proxy_feature_flags` |
| `zwave_proxy.feature_flags`, `zwave_proxy.home_id` | `zwave_proxy_feature_flags`, `zwave_home_id` |
| `serial_proxies` | `serial_proxies` |

## What espex implements

espex answers the request from the same state it builds
`DeviceInfoResponse` from (`Espex.DeviceConfig.to_device_capabilities_response/2`),
so the two answers on one connection always agree:

* the Bluetooth flags from the `:bluetooth_scanner` and
  `:bluetooth_proxy` adapters (`Espex.BluetoothScanner`,
  `Espex.BluetoothProxy`), including the optional callbacks each one
  exports;
* the Z-Wave flags and home id from `c:Espex.ZWaveProxy.feature_flags/0`
  and `c:Espex.ZWaveProxy.home_id/0`;
* the serial ports from `c:Espex.SerialProxy.list_instances/0`.

espex reports no voice assistant features and no Bluetooth MAC
address. Later versions add fields to this message: Sendspin and the
device wizard in [API 1.18](1.18.md).

## Usage

Nothing to configure: the answer follows the adapters you start espex
with.

    Espex.start_link(
      device_config: [name: "my-device"],
      bluetooth_proxy: MyApp.BLEProxy,
      serial_proxy: MyApp.SerialPorts
    )

Like `DeviceInfoResponse`, the answer is fixed when the connection is
accepted. After `Espex.update_adapters/2`, call
`Espex.disconnect_clients/1` so clients reconnect and ask again.

## Upgrade notes

None for adapters: the message is built from what they already report.