Old version of Aperture no longer working after Mac OSX update
I have an old version of Aperture (3.1.2) that no longer works on my mac following my update to OSX (10.9.4). I would like to update my Aperture version so that its compatible with OSX but am unable to do so. All the aperture downloads tell me I have to update through the App Store but the App Store does not recognize that I have a valid, if outdated, version of Aperture on my computer and wants me to buy the software again. Is there a way to update Aperture (for free) and keep my library of photos? Thank you
MacBook Pro, OS X Mavericks (10.9.4)