https://techcrunch.com/2018/07/26/slack-forms-key-alliance-as-atlassian-throws-in-the-towel-on-enterprise-collaboration/

With today’s announcement from Atlassian that it was selling the IP assets of its two enterprise communications tools, Hipchat and Stride, to Slack, it closes the book on one of the earliest competitors in the modern enterprise collaboration space. It was also a clear  signal that Slack is not afraid to take on its giant competitors by forming key alliances.

The fact the announcement came from Slack co-founder and CEO Stewart Butterfield on Twitter only exacerbated that fact. Atlassian has a set of popular developer tools like Jira, Confluence and Bitbucket. At this point, Hipchat and Stride had really become superfluous to the company and they sold the IP to their competitor.