It's not clear to me how the nodes authenticate a new node on node replacement. They say that the nodes check the new node's MRENCLAVE value, so what happens i

It's not clear to me how the nodes authenticate a new node on node replacement. They say that the nodes check the new node's MRENCLAVE value, so what happens if there is a software update and the MRENCLAVE value has to change? How do the old nodes know what the new MRENCLAVE value should be?