Q: backup from ios 10 to ios 9.3

So I upgraded to ios 10 PB without doing a backu. I did a backup while using ios 10. I downgraded to 9.3 and when trying to restore from the backup I did, it said my OS version is too old. Do I have to wait to ios 10 official release to restore my backup to my iPhone? What can I do ? Sorry for my english.