retrieve changes made by other people despite how long ago it was.
when multiple work on the presentation its easy to miss things and easily delete things. it will be good to be able to go back and retrieve things from previous saves so work doesn't get lost.
Now you can view the history of your file by going to File>Info>Version History. To retrieve content from the file, you can save a copy of an older version and retrieve the content from the older version. Hope that helps. Thanks for using PowerPoint!