Swapping Pi with a new one, how far back in Pi configuration do I need to go?

[FlaMike]

I am swapping a suspect pi with a new one. I am planning to use the same SD card and config from the old Pi in the new one. I plugged the Pi into the stack and turned it back on. The router assisgned a different IP address since the mac address is different. OK, I'm going to new ip addresss:5150 to get to Nixie. The Dash Panel comes up, but the title bar says Unknown Model and Not Connected. And I can't find REM, even using the (new) correct IP address. I get a HTTP: 404 not found error.

How far back in the configuration process do I need to go? If I change the IP address of the Pi at the router to the old Pi's, or spoof the old Pi's mac address, can I move forward from that point? If not, how far back in the setup process do I need to go? Hoping I can get tthings going without starting from scratch.

Thanks for your help!

[FlaMike]

Sweated through recinfiguring the new pi--restoring from back didn't do the trick & not sure why, but all much better now.