Posted 27 October 2012 - 15:28
First of all, Apple DRM locks every app you download off of the app store (even free ones). Even if you did find the previous version of the app somewhere it would need to be cracked and you would need to have a JB iOS to install it.
Have you been backing your iOS up with iTunes? If you haven't backed up your device with iTunes recently there is a chance that it still has the older version in its app. Goto iTunes->Apps, find the App and check what version it is. Copy the app (drag and drop) to your desktop or some other folder (for safe keeping). Uninstall the app on your iOS device, plug it in and sync. Re-check that app so that iTunes installs its version on the iOS device.
If you do incremental backups of your computer (like with TimeMachine if you are on Mac), then you should be able to dig up the old version through that. The key is finding the one that is signed with your Apple iD.
If you backup via iCloud than i think you are SOL because none of your apps would have been stored in iTunes I don't think. I don't really like the iCloud backup option. I like to manage my own backups and have piece of mind that my own redundancy scheme works.