In order to support Pocket Frogs in the latest version of iOS we can only support devices running iOS 4.3 and newer. This is based on Apple's choice to drop support for these older devices within the latest version of their developer tools. In a recent update of Pocket Frogs (Version 2.0) we had to remove Plus+ because it is also no longer being supported and the app now uses Game Center for backups.
If you have an older device with a copy of your game installed, you will need to use an iTunes/iCloud device backup to backup the old device and then restore the new device from this backup. This will put the old Pocket Frogs game data on the new device. Since iTunes doesn't allow players to selectively restore apps this would restore the entire device backup to be restored.
Please see the following link for more information on backing up and restoring with iTunes and iCloud: http://support.apple.com/kb/ht1766
If restoring from iTunes, once the app is installed on the newer device and your data restored you can update the app to the latest version as long as your new device has iOS 4.3 or newer installed. Enabling Game Center on the Pocket Frogs Menu before updating will sync your awards to Game Center and make sure they are saved.