Where can I find old copies of a shared excel file?
 

I am using a excel sheet that is shared by several people and someone pasted
in irrelevant text in several cells and then saved.

I would like to know how to go back in time and restore the older file. How
to do that? I looked at the settings for shared excel sheet and it said it
was set to 30 days, so it must be stored somewhere. Thanks in advance.