To help Yammer customers migrate to a modern browser, use of Yammer together with Internet Explorer 10 is supported until March 1, 2018. From that day forward, the Yammer system requirements will be consistent with those of Office 365.
After this date, Yammer Embed will be updated to require the Internet Explorer 11 (Edge) Document mode. Any site hosting Yammer Embed must be updated to use this Document mode. As the default document mode for SharePoint Online is updated to be Edge mode, changes are not required unless sites are customized. Other products such as on-premises deployments of SharePoint and third-party products must be updated to use the new document mode.
Using Yammer together with Internet Explorer 8 or Internet Explorer 9 is no longer supported.