Comment 6 for bug 955673

Can you clarify please how exactly you performed this "migration" to 12.04? If you upgrade to 12.04 using the update-manager, the related packages should appear under a heading of "No longer supported by Canonical" in a listing somewhere, and should give you the option to keep or remove them, assuming that they aren't simply just upgraded when doing the upgrade.

If you're just installing over top of an existing install, then you will have to migrate some data manually. For example, Evolution is not the default mail client in 12.04 either. It has been replaced with Thunderbird.