Can you restore an iPhone backup on iTunes to an older iPhone using an older version of IOS?

I am planning to swap iPhones with someone else. I have an iPhone 6 (using IOS 12.4.5) and they have an iPhone 8 (using IOS 13.3.1). I know that it is possible to transfer a backup of the iPhone 6 to the 8 through iTunes, but I am wondering whether I can do the opposite and transfer an iPhone 8 backup to the iPhone 6, running an older version of IOS?