The first time you run Aperture 1.1, you will see an alert message that lets you know that your Aperture Library will be converted to a new format.
Once converted, the Aperture Library will no longer work with Aperture 1.0 or 1.0.1.
Tip: If you want to maintain backward compatibility, make a copy of your Aperture Library before converting it.
By default, the Aperture Library is located in your Pictures folder. If you have selected a different location, it will be noted in Aperture Preferences.