To search for older asset versions, you will need to have these settings set to true in your ApplicationSettings.properties file:
and depending on whether you would like to have this functionality available to all users instead of just admins:
Non-admin users will only be able to see this checkbox if the version attribute is visible to them!
You can add a checkbox to search previous versions of assets when you are using the homepage search using the settings in Admin -> Attributes -> Display Attributes -> Searching -> Homepage -> Update the search settings.
The available settings let you control if the checkbox will appear and if it should be checked by default.