Going Back to Windows 8.1

Hi!

Just a quick question - after installing Windows 10 last weekend, for various reasons I am going back to Windows 8.1.  I wouldn't have thought this would have any implications in terms of my Norton AV subscription, but I thought I would throw it out to members of this forum in case there are issues I need to be aware of (esp. possibly having to purchase Norton AV again)?

Many thanks in advance!