diff --git a/docs/add-ons/configuration.md b/docs/add-ons/configuration.md
index 14d057b3..c90063cd 100644
--- a/docs/add-ons/configuration.md
+++ b/docs/add-ons/configuration.md
@@ -114,7 +114,7 @@ The configuration for an add-on is stored in `config.json`.
 | slug | string | yes | Slug of the add-on. This needs to be unique in the scope of the [repository](repository.md) that the add-on is published in and URI friendly.
 | description | string | yes | Description of the add-on.
 | arch | list | yes | List of supported arch: `armhf`, `armv7`, `aarch64`, `amd64`, `i386`.
-| machine | list | no | Default it support any machine type. You can select that this add-on run only on specific machines.
+| machine | list | no | Default it support any machine type. You can select that this add-on run only on specific machines. You can use `!` before a machine type to negate it.
 | url | url | no | Homepage of the add-on. Here you can explain the add-ons and options.
 | startup | string | yes | `initialize` will start add-on on setup of Home Assistant. `system` is for things like databases and not dependent on other things. `services` will start before Home Assistant, while `application` is started afterwards. Finally `once` is for applications that don't run as a daemon.
 | webui | string | no | An URL for web interface of this add-on. Like `http://[HOST]:[PORT:2839]/dashboard`, the port needs the internal port, which will be replaced with the effective port. It is also possible to bind the protocol part to a configuration options with: `[PROTO:option_name]://[HOST]:[PORT:2839]/dashboard` and it's looked up if it is `true` and it's going to `https`.