Is an android 5.1 adb backup incompatible with android 6.0? I recently loaded Cyanogenmod 13 on my nexus 4.  Prior to flashing, I did a full adb backup and an app data backup for com.king.candycrushsaga.  The only thing that seems to need restoring is the candycrush data, but adb restore doesn't seem to do the job.  It simply creates an empty folder in /sdcard/Android/data.

I used the abe.jar expander app to extract the .ab contents to a backup.tar file to see what was really in the backup, and there's an extensive set of files there, but they are all relative to apps/com.king.candycrushsaga.  I can't find any apps/com... structure on my phone now.  And since there's no 'data' component to file paths in the adb backup, it would seem that Android 6 stores app data in a different location than 5.1 did.  Is that true?  And if so, can I just use my .tar backup to restore the data to the correct location?  Or rebuild the .ab with a new top level directory?
ADB backups usually do not contain system apps, unless explicitly specified by you while performing the backup process. If this is the case, you can certainly restore safely without any problem. But some apps may be incompatible with 6.0 as such. So they may not work after the restore.