Do you mean it should automatically ask if you want to convert it to a private channel? You can manually convert to a private channel and keep message history.

Do you mean it should automatically ask if you want to convert it to a private channel? You can manually convert to a private channel and keep message history. https://slack.com/help/articles/217555437-Convert-a-group-direct-message-to-a-private-channel https://slack.com/help/articles/217555437-Convert-a-group-di...