I bought Scrivener 1.9 around three years ago. I now see that Scrivener 3 is available (for quite some time ), and I think I remember that there was a promise online, that Windows users can upgrade to 3 for free, once it’s there… or do I remember wrong?
You can try it for free. The trial is good for 30 non-continuous days.
(Although the upgrade might indeed be free for you, depending on when exactly you bought your V1 license. – See the second link below for that.)
The upgrade price and all else is here:
And this will be most useful to you should you upgrade: