The OP has a C-4 so the Hub Protection Service wouldn't offer migration. That's done (manually) via the Topic @bravenel made, which @ritchierich has suggested.
As @TechMedX suggests, we don't know what your goals are to make good suggestions, but for me, multiple hubs is a solution looking for a problem. Fortunately for me, I had problems that HubConnect solved. I've deduced that most/many Z-meshes are I/O bound, meaning they are a limited resource and more to the point, the resource is something we love to consume. We add devices as quickly as we can get them and some of them have extra features that can hurt in certain circumstances.. I'm thinking of power monitoring. The vendors default them to making power/voltage/current reports rather often. In no time at all, the Z-radios are processing very little other than power reports. That lead me to think about how to get more Z-radio bandwidth. Turning off chatty devices is one, but parallelism struck me early on as the answer. I limit myself to X devices per radio and even splitting my home into "upstairs" and "downstairs" sets of devices.
You can predict the future to some degree... most new devices will be introduced with S2. So you could start with using your C-4 for older non-S2 devices and use the C-7 for the newer S2 devices. You could split your home too.. maybe Front and Back or Left and Right. My point being, there's nothing obsolete in my collection of C-3s + C-4s + C-5s. They run my home quite well.