Migrate system information: Use this before restoring technique data from a distinct (incompatible) ROM, or even diverse phone model. Though it usually functions properly for the most common information (eg: SMS/MMS) from Android 1.5 to 2.2, this is a best effort method and is not assured to perform from any ROM to any ROM. All of us have a tendency to use a specific set of apps and games and preserve trying new ones often.