Upgrading FCP 10.4.10/Mojave to FCP 10.5/BigSur

I'm currently FCP 10.4.10 on Mojave and want to upgrade to BigSur, but I've read that 10.4.x will not run on BigSur, that I will need to upgrade to at least FCP 10.5. As I hold a current FCP 10.4 license, will I need to repurchase FCP 10.5 for $299 or can I upgrade for free or at a lesser cost?