Is V3+ backwards compatible?

I currently have the V1 set up, purchased about 10 years ago. Still working, but time for an upgrade as it’s now showing its limitations.

I’m going to put in the V3+ and ideally, will add one or more additional temp sensors, so that the system can be programmed to read different locations at different times, to reflect our use of the property. I don’t want smart TRVs.

As I have a fully functioning V1, I’m wondering if any of that kit could work alongside the new kit, so reducing my need to buy one or more additional sensors?

Could I run the V1 and V3 plus together? Could I add the v1 solar remote sensor to the V3 set up?

Wiring two stats isn’t an issue. I have a plan for that. My questions are really, can 2 Tado systems run together at the same property on the same account, or if not, can v3+ run any v1 kit (eg remote sensor)?

Anyone tried anything like this? Thanks.