I had my laptop halfway upgraded from Ubuntu 11.10 and 12.04 for a while. There was some reason for that which escapes me now, so I decided to complete the upgrade. So far only one issue has cropped up with an ecryptfs volume that I had created. It failed to mount with an error

Error attempting to evaluate mount options: [-22] Invalid argument

Based on a Redhat bug report I found, it looks like I need to SUID root /sbin/mount.ecryptfs.

chmod 4755 /sbin/mount.ecryptfs

Still haven't figured out why this change is necessary, but honestly once it worked again I stopped looking.