Homemade update Sony Xperia to Android 6.0 Marshmallow and DRM restoration I have a Xperia smartphone, Android 4.4.

Is it possible to upgrade my device with new Android 6.0 Marshmallow, and restore previously backed up DRM keys so Sony proprietary features can work as before? Or maybe the keys are bound to specific Android version?

I know about the tool Backup-TA and about the fact that Sony has recently released AOSP version for Xperias.

Please, if you can, give me answer which will be more than 'yes' or 'no', I always like to understand the way things are :)

PS. Sorry if this questions is unclear or could be a duplicate. Let me know about it please. I just could not find any information on the web about restoring DRM keys into new system version.
If you have a backup of your ta partition running a specific firmware it is for that specific firmware. Firmware in this case means the specific version of your firmware (e.g. build number). You cannot restore it.