Go to the "Add-ins" tab  ⇒  "Upgrader" panel  ⇒  "File Upgrader" to start the command

Clicking this button starts the command and launches the "Revit File Upgrader" dialog.

Under the "Source" text box, specify the location of the folder where previous versions of Revit files reside. In the "Destination" box, specify the folder where the upgraded filers will be saved.

If your files have RVT Links that have not been upgraded, you can prevent opening worksets that contain those links with the "Open Only Worksets Whose Name..." options.

Check the file types you would like to upgrade; you can upgrade .rvt, .rfa, and .rte files. Press the "Upgrade" button to start the upgrade.

Once the upgrade starts, Revit will open the files one by one and save them in the destination folder.

The progress can be monitored in the list box at the lower part of the dialog. After the upgrade process is completed, a dialog box is displayed with the total count of succeeded files and a total number of files confirming the completion of the upgrade. The status messages are also saved as a log file, UpgraderLog.txt.

The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin.

You may need to restart the Autodesk product to activate the app/plug-in.

To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 7/8.1/10) and uninstall as you would any other application from your system..