When you replace an asset, the previous version is saved under Versions. Only admin users with Administer File Versions turned on will see the versions panel in the Detail view.
Now, when you update an asset and want to have a new version, click the Ellipsis and hit Add New Version.
Admins with correct access can see the version history under Versions at bottom right of Details view. They can Download an older version or Revert to reinstate the older version.
You can add access to Admin users for older versions by selecting the Administer File Versions option from the permission list.
Once you have updated the permission you must click Save.