We are pleased to announce the launch of Edit post, one of our most frequently requested features! Starting today, Yammer users will be able to make changes to the text in a post or in an announcement after it has been published. After a post has been edited there will be a tag indicating that it has been edited, and users will be able to see the version history by clicking on that tag.
The Edit post feature is now available on web, and will be rolling out soon to iOS and Android. Note, users will need the latest version of the Yammer mobile app to enable Edit post on their mobile devices.
Currently, the Edit post feature does not support attachments and external groups but stay tuned for these additions in the future.
Source : techcommunity.microsoft.com
www.office.com/setup : Blogs