Slack

If you click the smiley face on the designer, you should be able to select your emoji from the pop-up menu. Otherwise if you want to type out the string it would have to be :flag_gb: (including the colons)

Glad it worked out, I'll look into ensuring we have support for all languages for file names for the next version of the activities.

Hi Bill,

Follow the steps in our Setup guide to allow messages to be sent as actual users or take a look at Slack's Create a Bot documentation to create individual bots. These bots will have an associated token beginning with xoxb that allow them to use the activities.

You should be able to send any type of file by using the send message activity. make sure that you have the Files permission selected in the slack scope. For more information, you can see our documentation for the send message activity HERE.