Does backup and restore work when restoring to an older Android version?

I'm getting a battery replacement on my Nexus 6P, and in the meantime I figured I'd use my Nexus 5. I did restored my accounts during the initial setup, but it gave me "no backups available for source device" during the restore step. The only thing I can think of is that the 5 is on Marshmallow, the 6p is on Nougat.