Thank you. I have now backed up my DRM keys. I have a few more questions:

1. My Xperia X is asking me to update my phone to Nougat. If I do so,
a. Will the DRM keys change?
b. Will I have to downgrade to Marshmallow again to install Sailfish OS?
c. If I upgrade my phone to Nougat, will doing a factory reset bring it back to Marshmallow? Will the backed up DRM keys still be relevant in that case?