* **Slack**: Removed _Mention_ setting and instead introduce _Mention Users_, _Mention Groups_, and _Mention Channel_. The first two settings require user and group IDs, respectively. This change was necessary because the way of mentioning via the Slack API [changed](https://api.slack.com/changelog/2017-09-the-one-about-usernames) and mentions in Slack notifications no longer worked.
### Notice about changes in backendSrv for plugin authors
To set up slack you need to configure an incoming webhook url at slack. You can follow their guide on how
to do that [here](https://api.slack.com/incoming-webhooks). If you want to include screenshots of the firing alerts
in the Slack messages you have to configure either the [external image destination](#external-image-store) in Grafana,
or a bot integration via Slack Apps. Follow Slack's guide to set up a bot integration and use the token provided
(https://api.slack.com/bot-users), which starts with "xoxb".
To set up Slack, you need to configure an incoming Slack webhook URL. You can follow
[their guide](https://api.slack.com/incoming-webhooks) on how to do that. If you want to include screenshots of the
firing alerts in the Slack messages you have to configure either the [external image destination](#external-image-store)
in Grafana, or a bot integration via Slack Apps. Follow Slack's guide to set up a bot integration and use the token
provided (https://api.slack.com/bot-users), which starts with "xoxb".
Setting | Description
---------- | -----------
Url | Slack incoming webhook url.
Url | Slack incoming webhook URL.
Username | Set the username for the bot's message.
Recipient | Allows you to override the Slack recipient.
Icon emoji | Provide an emoji to use as the icon for the bot's message. Ex :smile:
Icon URL | Provide a url to an image to use as the icon for the bot's message.
Mention | make it possible to include a mention in the Slack notification sent by Grafana. Ex @here or @channel
Mention Users | Optionally mention one or more users in the Slack notification sent by Grafana. You have to refer to users, comma-separated, via their corresponding Slack IDs (which you can find by clicking the overflow button on each user's Slack profile).
Mention Groups | Optionally mention one or more groups in the Slack notification sent by Grafana. You have to refer to groups, comma-separated, via their corresponding Slack IDs (which you can get from each group's Slack profile URL).
Mention Channel | Optionally mention either all channel members or just active ones.
Token | If provided, Grafana will upload the generated image via Slack's file.upload API method, not the external image destination.
If you are using the token for a slack bot, then you have to invite the bot to the channel you want to send notifications and add the channel to the recipient field.