If these appliances are brand new and never been licensed, you should be able to a 'set temp_license' to get going and then add permanent licenses afterwards. Hope this helps. Thomas

Yes you can mix hardware models whilst doing this, it's not supported for long term production running, but fine for short periods whilst doing the swapout, I have used this approach many times now.

I set up a farm of BIND resolvers at an ISP a few years ago and also never saw ...