EU antitrust regulators are following up on a complaint by Slack by asking Microsoft's rivals if its Teams app integrated with its Office product gives it greater clout, in a sign that they could open an investigation. From a report: In a questionnaire sent to rivals and seen by Reuters, the European Commission is focusing on the period 2016 to 2021. Microsoft introduced Teams in early 2017 to compete with Slack and others in the fast-growing workplace collaboration market. Slack, bought by business software maker Salesforce.com in July, took its grievance over Microsoft's Teams software to the Commission last year. Microsoft, which has been handed 2.2 billion euros ($2.6 billion) in EU fines for cases involving so-called tying and other practices in previous decade, declined to comment.Read more of this story at Slashdot. Click here to read full news..