Ok I'm jailbroken and after 4.0 the only thing I'll miss from jailbreak is grooveshark. I think I'm willing but not sure if I upgrade to 4.0 can I downgrade to 3.1.3 I hve my shsh blobs backed up but what am I suposed to do with them
No but that is before apple stops signing 3.1.3. Soon as apple stops signing 3.1.3 you cannot downgrade without shsh blobs