I need V.1.56.00. Do I have to jailbreak Iphone to get past releases?

Help! I mistakenly updated to the newest version IOS app and realized it supports BI4, but we're running BI3. IOS and Itunes suck in that there's no undo app change or a restore function. Deleted the app from the phone, but sad to find out there's no backup to restore from. Will I have to jailbreak this phone to get older releases? Kindly send link for the app install.

Why not upgrade to version 4 ... only $ 30 ... tons of new features.