If you select the Yes button to update Polarbar, a download will immediately start and Polarbar will automatically update the proper files to the newer version. It will then exit and restart itself once the application files are updated.
If you select the No button, it closes the dialog.
If you select the Download Only button, the download an internet file dialog will appear and you can save the file to a name of your choice, in a location of your choice.
If you select the Skip this Version button, Polarbar will no longer consider this newer version as appropriate to upgrade to and further checks will only notify you of a newer version than this one.