Will I lost my old GarageBand 5.1 Projects if I install the new one??

Will I lost my old GarageBand 5.1 Projects if I install the new one, 2.0.1 ?

There is not yet a GarageBand 5.1 on iOS devices? Are you asking about GarageBand on a Mac or on an iPad, iPhone, iPod?

If you want to know, what will happen, if you upgrade from GarageBand 1.x to GarageBand 2.x on your iPad, iPhone, iPod, then the answer is "No". GarageBand 2 will be able to open your old projects. But you will need to restore the old instruments. The newest GarageBand version is free, but does not include all instruments. You will have to use the "Restore Purchase" button to restore the instruments. See: Expanding GarageBand for iOS 2.0 content with an in-app purchase