I would like TIVO 4K. I currently have TIVO. Must I continue to pay TIVO after I set up 4K?

Owing mostly to TiVo's awful marketing, you've posted to the wrong forum. You're (possibly) looking for the TiVo Stream 4K forum; this forum is focused on the earlier TiVo Stream product, used for transcoding recorded and live content from a compatible TiVo DVR to mobile devices.

That said, the Stream 4K doesn't require a service plan. See: TiVo Service Plans and Policies: Essentials

 

p.s. Saying "I would like TIVO 4k" is ambiguous. TiVo has several 4K products within its DVR ecosystem, and now has released a 4K-capable streaming device that has no crossover functionality with their DVR products.