So you'd be OK paying a one time fee in order to own that version forever?

Because that's literally how JetBrains works:

12 months of uninterrupted subscription payments qualify you for receiving a perpetual fallback license.

https://sales.jetbrains.com/hc/en-gb/articles/207240845-What-is-perpetual-fallback-license-

(I promise I'm not a sales rep)