To restore one of those versions, hover the mouse
cursor over the date and time for that version, and then open the
drop-down menu that appears. From the drop-down menu, select Restore
(see Figure 1).
Figure 1. Selecting Restore brings back an earlier version of a file or list item.
Selecting the Restore option
creates a new version for the file or list item and increases its
version number. If the list or library requires check-in or publishing,
the new version still must be checked in after the restoration.
A version can be restored only if the file is not checked out by someone else.